661515195156 has 24 divisors (see below), whose sum is σ = 1568839317024. Its totient is φ = 216890227680.

The previous prime is 661515195151. The next prime is 661515195157. The reversal of 661515195156 is 651591515166.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 661515195099 and 661515195108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661515195151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 451853910 + ... + 451855373.

It is an arithmetic number, because the mean of its divisors is an integer number (65368304876).

Almost surely, 2^661515195156 is an apocalyptic number.

It is an amenable number.

661515195156 is an abundant number, since it is smaller than the sum of its proper divisors (907324121868).

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

661515195156 is a wasteful number, since it uses less digits than its factorization.

661515195156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 903709351 (or 903709349 counting only the distinct ones).

The product of its digits is 1215000, while the sum is 51.

The spelling of 661515195156 in words is "six hundred sixty-one billion, five hundred fifteen million, one hundred ninety-five thousand, one hundred fifty-six".