391665525942 has 16 divisors (see below), whose sum is σ = 784652022000. Its totient is φ = 130335013632.

The previous prime is 391665525917. The next prime is 391665525971. The reversal of 391665525942 is 249525566193.

It is a super-2 number, since 2×391665525942² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55036567 + ... + 55043682.

It is an arithmetic number, because the mean of its divisors is an integer number (49040751375).

Almost surely, 2^391665525942 is an apocalyptic number.

391665525942 is an abundant number, since it is smaller than the sum of its proper divisors (392986496058).

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

391665525942 is a wasteful number, since it uses less digits than its factorization.

391665525942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110080847.

The product of its digits is 17496000, while the sum is 57.

The spelling of 391665525942 in words is "three hundred ninety-one billion, six hundred sixty-five million, five hundred twenty-five thousand, nine hundred forty-two".