21534513 has 64 divisors (see below), whose sum is σ = 39481344. Its totient is φ = 10080000.

The previous prime is 21534511. The next prime is 21534517. The reversal of 21534513 is 31543512.

It is not a de Polignac number, because 21534513 - 2¹ = 21534511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21534511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 213163 + ... + 213263.

It is an arithmetic number, because the mean of its divisors is an integer number (616896).

Almost surely, 2^21534513 is an apocalyptic number.

It is an amenable number.

21534513 is a deficient number, since it is larger than the sum of its proper divisors (17946831).

21534513 is a wasteful number, since it uses less digits than its factorization.

21534513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206.

The product of its digits is 1800, while the sum is 24.

The square root of 21534513 is about 4640.5293879039. The cubic root of 21534513 is about 278.2135972087.

It can be divided in two parts, 2153 and 4513, that added together give a palindrome (6666).

The spelling of 21534513 in words is "twenty-one million, five hundred thirty-four thousand, five hundred thirteen".