21845579 has 16 divisors (see below), whose sum is σ = 25858560. Its totient is φ = 18066240.

The previous prime is 21845563. The next prime is 21845597. The reversal of 21845579 is 97554812.

It is not a de Polignac number, because 21845579 - 2⁴ = 21845563 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is not an unprimeable number, because it can be changed into a prime (21845519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29192 + ... + 29930.

It is an arithmetic number, because the mean of its divisors is an integer number (1616160).

Almost surely, 2^21845579 is an apocalyptic number.

21845579 is a deficient number, since it is larger than the sum of its proper divisors (4012981).

21845579 is a wasteful number, since it uses less digits than its factorization.

21845579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 890.

The product of its digits is 100800, while the sum is 41.

The square root of 21845579 is about 4673.9254380018. The cubic root of 21845579 is about 279.5467966101.

The spelling of 21845579 in words is "twenty-one million, eight hundred forty-five thousand, five hundred seventy-nine".