21884557 has 4 divisors (see below), whose sum is σ = 21901600. Its totient is φ = 21867516.

The previous prime is 21884539. The next prime is 21884573. The reversal of 21884557 is 75548812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21884557 - 2¹⁵ = 21851789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21884507) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6423 + ... + 9220.

It is an arithmetic number, because the mean of its divisors is an integer number (5475400).

Almost surely, 2^21884557 is an apocalyptic number.

It is an amenable number.

21884557 is a deficient number, since it is larger than the sum of its proper divisors (17043).

21884557 is a wasteful number, since it uses less digits than its factorization.

21884557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17042.

The product of its digits is 89600, while the sum is 40.

The square root of 21884557 is about 4678.0933081759. The cubic root of 21884557 is about 279.7129583913.

The spelling of 21884557 in words is "twenty-one million, eight hundred eighty-four thousand, five hundred fifty-seven".