21053715 has 16 divisors (see below), whose sum is σ = 34015488. Its totient is φ = 11118816.

The previous prime is 21053713. The next prime is 21053731. The reversal of 21053715 is 51735012.

It is not a de Polignac number, because 21053715 - 2¹ = 21053713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21053713) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5269 + ... + 8358.

It is an arithmetic number, because the mean of its divisors is an integer number (2125968).

Almost surely, 2^21053715 is an apocalyptic number.

21053715 is a deficient number, since it is larger than the sum of its proper divisors (12961773).

21053715 is a wasteful number, since it uses less digits than its factorization.

21053715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13738.

The product of its (nonzero) digits is 1050, while the sum is 24.

The square root of 21053715 is about 4588.4327389644. The cubic root of 21053715 is about 276.1274484905.

Adding to 21053715 its reverse (51735012), we get a palindrome (72788727).

The spelling of 21053715 in words is "twenty-one million, fifty-three thousand, seven hundred fifteen".