861660079128 has 32 divisors (see below), whose sum is σ = 2393500220400. Its totient is φ = 287220026304.

The previous prime is 861660079121. The next prime is 861660079151. The reversal of 861660079128 is 821970066168.

861660079128 is a `hidden beast` number, since 8 + 6 + 1 + 6 + 600 + 7 + 9 + 1 + 28 = 666.

It is a hoax number, since the sum of its digits (54) 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 (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861660079121) 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, 1994583301 + ... + 1994583732.

Almost surely, 2^861660079128 is an apocalyptic number.

It is an amenable number.

861660079128 is an abundant number, since it is smaller than the sum of its proper divisors (1531840141272).

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

861660079128 is a wasteful number, since it uses less digits than its factorization.

861660079128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3989167048 (or 3989167038 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The spelling of 861660079128 in words is "eight hundred sixty-one billion, six hundred sixty million, seventy-nine thousand, one hundred twenty-eight".