3157921 has 8 divisors (see below), whose sum is σ = 3414824. Its totient is φ = 2903040.

The previous prime is 3157919. The next prime is 3157927. The reversal of 3157921 is 1297513.

It can be written as a sum of positive squares in 4 ways, for example, as 112896 + 3045025 = 336^2 + 1745^2 .

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 3157921 - 2¹ = 3157919 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 3157921.

It is not an unprimeable number, because it can be changed into a prime (3157927) 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, 5185 + ... + 5761.

It is an arithmetic number, because the mean of its divisors is an integer number (426853).

Almost surely, 2^3157921 is an apocalyptic number.

It is an amenable number.

3157921 is a deficient number, since it is larger than the sum of its proper divisors (256903).

3157921 is a wasteful number, since it uses less digits than its factorization.

3157921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1011.

The product of its digits is 1890, while the sum is 28.

The square root of 3157921 is about 1777.0540228142. The cubic root of 3157921 is about 146.7124896995.

The spelling of 3157921 in words is "three million, one hundred fifty-seven thousand, nine hundred twenty-one".