391825732921 has 48 divisors (see below), whose sum is σ = 475759614528. Its totient is φ = 321469948800.

The previous prime is 391825732897. The next prime is 391825732939. The reversal of 391825732921 is 129237528193.

It is not a de Polignac number, because 391825732921 - 2⁹ = 391825732409 is a prime.

It is a hoax number, since the sum of its digits (52) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391825732951) 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, 131881966 + ... + 131884936.

It is an arithmetic number, because the mean of its divisors is an integer number (9911658636).

Almost surely, 2^391825732921 is an apocalyptic number.

It is an amenable number.

391825732921 is a deficient number, since it is larger than the sum of its proper divisors (83933881607).

391825732921 is a wasteful number, since it uses less digits than its factorization.

391825732921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4262 (or 4255 counting only the distinct ones).

The product of its digits is 1632960, while the sum is 52.

The spelling of 391825732921 in words is "three hundred ninety-one billion, eight hundred twenty-five million, seven hundred thirty-two thousand, nine hundred twenty-one".