21479911 has 2 divisors, whose sum is σ = 21479912. Its totient is φ = 21479910.

The previous prime is 21479881. The next prime is 21479917. The reversal of 21479911 is 11997412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21479911 is a prime.

It is a super-2 number, since 2×21479911² = 922773153135842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21479917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739955 + 10739956.

It is an arithmetic number, because the mean of its divisors is an integer number (10739956).

Almost surely, 2^21479911 is an apocalyptic number.

21479911 is a deficient number, since it is larger than the sum of its proper divisors (1).

21479911 is an equidigital number, since it uses as much as digits as its factorization.

21479911 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 34.

The square root of 21479911 is about 4634.6424889089. The cubic root of 21479911 is about 277.9782559809.

The spelling of 21479911 in words is "twenty-one million, four hundred seventy-nine thousand, nine hundred eleven".