21554955 has 12 divisors (see below), whose sum is σ = 37362000. Its totient is φ = 11495952.

The previous prime is 21554947. The next prime is 21554969. The reversal of 21554955 is 55945512.

It is not a de Polignac number, because 21554955 - 2³ = 21554947 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 239455 + ... + 239544.

It is an arithmetic number, because the mean of its divisors is an integer number (3113500).

Almost surely, 2^21554955 is an apocalyptic number.

21554955 is a deficient number, since it is larger than the sum of its proper divisors (15807045).

21554955 is a wasteful number, since it uses less digits than its factorization.

21554955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479010 (or 479007 counting only the distinct ones).

The product of its digits is 45000, while the sum is 36.

The square root of 21554955 is about 4642.7314158801. The cubic root of 21554955 is about 278.3016023524.

The spelling of 21554955 in words is "twenty-one million, five hundred fifty-four thousand, nine hundred fifty-five".