21753156 has 12 divisors (see below), whose sum is σ = 50757392. Its totient is φ = 7251048.

The previous prime is 21753131. The next prime is 21753163. The reversal of 21753156 is 65135712.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 906370 + ... + 906393.

Almost surely, 2^21753156 is an apocalyptic number.

It is an amenable number.

21753156 is an abundant number, since it is smaller than the sum of its proper divisors (29004236).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21753156 is a wasteful number, since it uses less digits than its factorization.

21753156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1812770 (or 1812768 counting only the distinct ones).

The product of its digits is 6300, while the sum is 30.

The square root of 21753156 is about 4664.0278729870. The cubic root of 21753156 is about 279.1520092500.

Adding to 21753156 its reverse (65135712), we get a palindrome (86888868).

The spelling of 21753156 in words is "twenty-one million, seven hundred fifty-three thousand, one hundred fifty-six".