21553772 has 12 divisors (see below), whose sum is σ = 38174136. Its totient is φ = 10646880.

The previous prime is 21553717. The next prime is 21553787. The reversal of 21553772 is 27735512.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 32129 + ... + 32792.

It is an arithmetic number, because the mean of its divisors is an integer number (3181178).

Almost surely, 2^21553772 is an apocalyptic number.

It is an amenable number.

21553772 is a deficient number, since it is larger than the sum of its proper divisors (16620364).

21553772 is a wasteful number, since it uses less digits than its factorization.

21553772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65008 (or 65006 counting only the distinct ones).

The product of its digits is 14700, while the sum is 32.

The square root of 21553772 is about 4642.6040106819. The cubic root of 21553772 is about 278.2965109195.

The spelling of 21553772 in words is "twenty-one million, five hundred fifty-three thousand, seven hundred seventy-two".