21315464 has 32 divisors (see below), whose sum is σ = 41904000. Its totient is φ = 10151232.

The previous prime is 21315451. The next prime is 21315491. The reversal of 21315464 is 46451312.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17747 + ... + 18909.

It is an arithmetic number, because the mean of its divisors is an integer number (1309500).

Almost surely, 2^21315464 is an apocalyptic number.

It is an amenable number.

21315464 is a deficient number, since it is larger than the sum of its proper divisors (20588536).

21315464 is a wasteful number, since it uses less digits than its factorization.

21315464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1277 (or 1273 counting only the distinct ones).

The product of its digits is 2880, while the sum is 26.

The square root of 21315464 is about 4616.8673361924. The cubic root of 21315464 is about 277.2670512108.

Adding to 21315464 its reverse (46451312), we get a palindrome (67766776).

The spelling of 21315464 in words is "twenty-one million, three hundred fifteen thousand, four hundred sixty-four".