21478579 has 2 divisors, whose sum is σ = 21478580. Its totient is φ = 21478578.

The previous prime is 21478553. The next prime is 21478627. The reversal of 21478579 is 97587412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21478579 - 2¹³ = 21470387 is a prime.

It is a super-2 number, since 2×21478579² = 922658711718482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21478519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739289 + 10739290.

It is an arithmetic number, because the mean of its divisors is an integer number (10739290).

Almost surely, 2^21478579 is an apocalyptic number.

21478579 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478579 is an equidigital number, since it uses as much as digits as its factorization.

21478579 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141120, while the sum is 43.

The square root of 21478579 is about 4634.4987862767. The cubic root of 21478579 is about 277.9725099191.

The spelling of 21478579 in words is "twenty-one million, four hundred seventy-eight thousand, five hundred seventy-nine".