661015876320 has 576 divisors, whose sum is σ = 2448775929600. Its totient is φ = 161827061760.

The previous prime is 661015876271. The next prime is 661015876333. The reversal of 661015876320 is 23678510166.

661015876320 is a `hidden beast` number, since 6 + 6 + 1 + 0 + 1 + 5 + 8 + 7 + 632 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 154116736 + ... + 154121024.

It is an arithmetic number, because the mean of its divisors is an integer number (4251347100).

Almost surely, 2^661015876320 is an apocalyptic number.

661015876320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661015876320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1224387964800).

661015876320 is an abundant number, since it is smaller than the sum of its proper divisors (1787760053280).

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

661015876320 is a wasteful number, since it uses less digits than its factorization.

661015876320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4503 (or 4492 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 661015876320 in words is "six hundred sixty-one billion, fifteen million, eight hundred seventy-six thousand, three hundred twenty".