21854553 has 16 divisors (see below), whose sum is σ = 33546240. Its totient is φ = 12396816.

The previous prime is 21854543. The next prime is 21854561. The reversal of 21854553 is 35545812.

It is not a de Polignac number, because 21854553 - 2¹⁰ = 21853529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21854533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 825 + ... + 6662.

It is an arithmetic number, because the mean of its divisors is an integer number (2096640).

Almost surely, 2^21854553 is an apocalyptic number.

It is an amenable number.

21854553 is a deficient number, since it is larger than the sum of its proper divisors (11691687).

21854553 is a wasteful number, since it uses less digits than its factorization.

21854553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7636.

The product of its digits is 24000, while the sum is 33.

The square root of 21854553 is about 4674.8853461876. The cubic root of 21854553 is about 279.5850699456.

The spelling of 21854553 in words is "twenty-one million, eight hundred fifty-four thousand, five hundred fifty-three".