661618246627296 has 288 divisors, whose sum is σ = 2263519002850560. Its totient is φ = 179077662978048.

The previous prime is 661618246627291. The next prime is 661618246627309. The reversal of 661618246627296 is 692726642816166.

It is a happy number.

661618246627296 is a `hidden beast` number, since 6 + 6 + 1 + 6 + 1 + 8 + 2 + 466 + 2 + 72 + 96 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a hoax number, since the sum of its digits (72) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661618246627291) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1023811035 + ... + 1024457061.

It is an arithmetic number, because the mean of its divisors is an integer number (7859440982120).

Almost surely, 2^{661618246627296} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661618246627296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1131759501425280).

661618246627296 is an abundant number, since it is smaller than the sum of its proper divisors (1601900756223264).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661618246627296 is a wasteful number, since it uses less digits than its factorization.

661618246627296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 672806 (or 672795 counting only the distinct ones).

The product of its digits is 752467968, while the sum is 72.

The spelling of 661618246627296 in words is "six hundred sixty-one trillion, six hundred eighteen billion, two hundred forty-six million, six hundred twenty-seven thousand, two hundred ninety-six".