21504889 has 4 divisors (see below), whose sum is σ = 24577024. Its totient is φ = 18432756.

The previous prime is 21504877. The next prime is 21504893. The reversal of 21504889 is 98840512.

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 21504889 - 2²¹ = 19407737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21504809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1536057 + ... + 1536070.

It is an arithmetic number, because the mean of its divisors is an integer number (6144256).

Almost surely, 2^21504889 is an apocalyptic number.

It is an amenable number.

21504889 is a deficient number, since it is larger than the sum of its proper divisors (3072135).

21504889 is an equidigital number, since it uses as much as digits as its factorization.

21504889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3072134.

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 21504889 is about 4637.3364122091. The cubic root of 21504889 is about 278.0859636161.

The spelling of 21504889 in words is "twenty-one million, five hundred four thousand, eight hundred eighty-nine".