319891021 has 4 divisors (see below), whose sum is σ = 320038432. Its totient is φ = 319743612.

The previous prime is 319891003. The next prime is 319891067. The reversal of 319891021 is 120198913.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 120198913 = 10691 ⋅11243.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-319891021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (319891001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70401 + ... + 74806.

It is an arithmetic number, because the mean of its divisors is an integer number (80009608).

Almost surely, 2^319891021 is an apocalyptic number.

It is an amenable number.

319891021 is a deficient number, since it is larger than the sum of its proper divisors (147411).

319891021 is a wasteful number, since it uses less digits than its factorization.

319891021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147410.

The product of its (nonzero) digits is 3888, while the sum is 34.

The square root of 319891021 is about 17885.4975049619. The cubic root of 319891021 is about 683.9127234093.

The spelling of 319891021 in words is "three hundred nineteen million, eight hundred ninety-one thousand, twenty-one".