315220421 has 4 divisors (see below), whose sum is σ = 320563200. Its totient is φ = 309877644.

The previous prime is 315220403. The next prime is 315220429. The reversal of 315220421 is 124022513.

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: 124022513 = 5867 ⋅21139.

It is a cyclic number.

It is not a de Polignac number, because 315220421 - 2⁶ = 315220357 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 315220393 and 315220402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (315220429) 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, 2671301 + ... + 2671418.

It is an arithmetic number, because the mean of its divisors is an integer number (80140800).

Almost surely, 2^315220421 is an apocalyptic number.

It is an amenable number.

315220421 is a deficient number, since it is larger than the sum of its proper divisors (5342779).

315220421 is an equidigital number, since it uses as much as digits as its factorization.

315220421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5342778.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 315220421 is about 17754.4479215773. The cubic root of 315220421 is about 680.5678798604.

Adding to 315220421 its reverse (124022513), we get a palindrome (439242934).

The spelling of 315220421 in words is "three hundred fifteen million, two hundred twenty thousand, four hundred twenty-one".