21055772 has 12 divisors (see below), whose sum is σ = 37292136. Its totient is φ = 10400880.

The previous prime is 21055763. The next prime is 21055799. The reversal of 21055772 is 27755012.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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, 31379 + ... + 32042.

It is an arithmetic number, because the mean of its divisors is an integer number (3107678).

Almost surely, 2^21055772 is an apocalyptic number.

It is an amenable number.

21055772 is a deficient number, since it is larger than the sum of its proper divisors (16236364).

21055772 is a wasteful number, since it uses less digits than its factorization.

21055772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63508 (or 63506 counting only the distinct ones).

The product of its (nonzero) digits is 4900, while the sum is 29.

The square root of 21055772 is about 4588.6568841002. The cubic root of 21055772 is about 276.1364409757.

The spelling of 21055772 in words is "twenty-one million, fifty-five thousand, seven hundred seventy-two".