21676579 has 2 divisors, whose sum is σ = 21676580. Its totient is φ = 21676578.

The previous prime is 21676553. The next prime is 21676607. The reversal of 21676579 is 97567612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21676579 - 2¹⁹ = 21152291 is a prime.

It is not a weakly prime, because it can be changed into another prime (21676279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10838289 + 10838290.

It is an arithmetic number, because the mean of its divisors is an integer number (10838290).

Almost surely, 2^21676579 is an apocalyptic number.

21676579 is a deficient number, since it is larger than the sum of its proper divisors (1).

21676579 is an equidigital number, since it uses as much as digits as its factorization.

21676579 is an evil number, because the sum of its binary digits is even.

The product of its digits is 158760, while the sum is 43.

The square root of 21676579 is about 4655.8113149053. The cubic root of 21676579 is about 278.8240605695.

The spelling of 21676579 in words is "twenty-one million, six hundred seventy-six thousand, five hundred seventy-nine".