391021231 has 8 divisors (see below), whose sum is σ = 400484304. Its totient is φ = 381575040.

The previous prime is 391021219. The next prime is 391021237. The reversal of 391021231 is 132120193.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 391021231 - 2¹⁵ = 390988463 is a prime.

It is a super-2 number, since 2×391021231² = 305795206185510722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391021237) 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, 51351 + ... + 58471.

It is an arithmetic number, because the mean of its divisors is an integer number (50060538).

Almost surely, 2^391021231 is an apocalyptic number.

391021231 is a deficient number, since it is larger than the sum of its proper divisors (9463073).

391021231 is a wasteful number, since it uses less digits than its factorization.

391021231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8441.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 391021231 is about 19774.2567749081. The cubic root of 391021231 is about 731.2515161436.

The spelling of 391021231 in words is "three hundred ninety-one million, twenty-one thousand, two hundred thirty-one".