21540136 has 16 divisors (see below), whose sum is σ = 40842900. Its totient is φ = 10648704.

The previous prime is 21540083. The next prime is 21540157. The reversal of 21540136 is 63104512.

It can be written as a sum of positive squares in 2 ways, for example, as 21215236 + 324900 = 4606^2 + 570^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14415 + ... + 15838.

Almost surely, 2^21540136 is an apocalyptic number.

It is an amenable number.

21540136 is a deficient number, since it is larger than the sum of its proper divisors (19302764).

21540136 is a wasteful number, since it uses less digits than its factorization.

21540136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30348 (or 30344 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21540136 is about 4641.1352059599. The cubic root of 21540136 is about 278.2378104165.

Adding to 21540136 its reverse (63104512), we get a palindrome (84644648).

The spelling of 21540136 in words is "twenty-one million, five hundred forty thousand, one hundred thirty-six".