661626331650 has 96 divisors (see below), whose sum is σ = 1823918886720. Its totient is φ = 176359098240.

The previous prime is 661626331627. The next prime is 661626331651. The reversal of 661626331650 is 56133626166.

661626331650 is a `hidden beast` number, since 6 + 6 + 1 + 6 + 2 + 633 + 1 + 6 + 5 + 0 = 666.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 661626331596 and 661626331605.

It is not an unprimeable number, because it can be changed into a prime (661626331651) 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, 3128149 + ... + 3332951.

It is an arithmetic number, because the mean of its divisors is an integer number (18999155070).

Almost surely, 2^661626331650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661626331650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (911959443360).

661626331650 is an abundant number, since it is smaller than the sum of its proper divisors (1162292555070).

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

661626331650 is a wasteful number, since it uses less digits than its factorization.

661626331650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207217 (or 207206 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 45.

The spelling of 661626331650 in words is "six hundred sixty-one billion, six hundred twenty-six million, three hundred thirty-one thousand, six hundred fifty".