315644921 has 4 divisors (see below), whose sum is σ = 315743844. Its totient is φ = 315546000.

The previous prime is 315644843. The next prime is 315644941. The reversal of 315644921 is 129446513.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129446513 = 7 ⋅18492359.

It can be written as a sum of positive squares in 2 ways, for example, as 117961321 + 197683600 = 10861^2 + 14060^2 .

It is a cyclic number.

It is not a de Polignac number, because 315644921 - 2²² = 311450617 is a prime.

It is a super-4 number, since 4×315644921⁴ (a number of 35 digits) contains 4444 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (315644941) 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, 44510 + ... + 51111.

It is an arithmetic number, because the mean of its divisors is an integer number (78935961).

Almost surely, 2^315644921 is an apocalyptic number.

It is an amenable number.

315644921 is a deficient number, since it is larger than the sum of its proper divisors (98923).

315644921 is an equidigital number, since it uses as much as digits as its factorization.

315644921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98922.

The product of its digits is 25920, while the sum is 35.

The square root of 315644921 is about 17766.3986502611. The cubic root of 315644921 is about 680.8732444637.

The spelling of 315644921 in words is "three hundred fifteen million, six hundred forty-four thousand, nine hundred twenty-one".