391221901 has 12 divisors (see below), whose sum is σ = 474960928. Its totient is φ = 315605952.

The previous prime is 391221889. The next prime is 391221923. The reversal of 391221901 is 109122193.

It is not a de Polignac number, because 391221901 - 2⁷ = 391221773 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 391221901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391221101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94671 + ... + 98716.

Almost surely, 2^391221901 is an apocalyptic number.

It is an amenable number.

391221901 is a deficient number, since it is larger than the sum of its proper divisors (83739027).

391221901 is a wasteful number, since it uses less digits than its factorization.

391221901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193428 (or 193411 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 391221901 is about 19779.3301453816. The cubic root of 391221901 is about 731.3765862039.

The spelling of 391221901 in words is "three hundred ninety-one million, two hundred twenty-one thousand, nine hundred one".