21465979 has 2 divisors, whose sum is σ = 21465980. Its totient is φ = 21465978.

The previous prime is 21465973. The next prime is 21466021. The reversal of 21465979 is 97956412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21465979 - 2³ = 21465971 is a prime.

It is not a weakly prime, because it can be changed into another prime (21465971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10732989 + 10732990.

It is an arithmetic number, because the mean of its divisors is an integer number (10732990).

Almost surely, 2^21465979 is an apocalyptic number.

21465979 is a deficient number, since it is larger than the sum of its proper divisors (1).

21465979 is an equidigital number, since it uses as much as digits as its factorization.

21465979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 43.

The square root of 21465979 is about 4633.1392165572. The cubic root of 21465979 is about 277.9181435241.

The spelling of 21465979 in words is "twenty-one million, four hundred sixty-five thousand, nine hundred seventy-nine".