21553554 has 32 divisors (see below), whose sum is σ = 48651840. Its totient is φ = 6305600.

The previous prime is 21553531. The next prime is 21553613. The reversal of 21553554 is 45535512.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3717 + ... + 7544.

It is an arithmetic number, because the mean of its divisors is an integer number (1520370).

Almost surely, 2^21553554 is an apocalyptic number.

21553554 is an abundant number, since it is smaller than the sum of its proper divisors (27098286).

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

21553554 is a wasteful number, since it uses less digits than its factorization.

21553554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11306.

The product of its digits is 15000, while the sum is 30.

The square root of 21553554 is about 4642.5805324194. The cubic root of 21553554 is about 278.2955726639.

The spelling of 21553554 in words is "twenty-one million, five hundred fifty-three thousand, five hundred fifty-four".