661643316452136 has 64 divisors (see below), whose sum is σ = 1668769830817920. Its totient is φ = 218592954961920.

The previous prime is 661643316452057. The next prime is 661643316452141. The reversal of 661643316452136 is 631254613346166.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 195820896 + ... + 199171056.

It is an arithmetic number, because the mean of its divisors is an integer number (26074528606530).

Almost surely, 2^{661643316452136} is an apocalyptic number.

It is an amenable number.

661643316452136 is an abundant number, since it is smaller than the sum of its proper divisors (1007126514365784).

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

661643316452136 is a wasteful number, since it uses less digits than its factorization.

661643316452136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3423106 (or 3423102 counting only the distinct ones).

The product of its digits is 33592320, while the sum is 57.

The spelling of 661643316452136 in words is "six hundred sixty-one trillion, six hundred forty-three billion, three hundred sixteen million, four hundred fifty-two thousand, one hundred thirty-six".