21262399 has 2 divisors, whose sum is σ = 21262400. Its totient is φ = 21262398.

The previous prime is 21262363. The next prime is 21262411. The reversal of 21262399 is 99326212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21262399 - 2⁹ = 21261887 is a prime.

It is a super-2 number, since 2×21262399² = 904179222470402, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21262999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10631199 + 10631200.

It is an arithmetic number, because the mean of its divisors is an integer number (10631200).

Almost surely, 2^21262399 is an apocalyptic number.

21262399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21262399 is an equidigital number, since it uses as much as digits as its factorization.

21262399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 34.

The square root of 21262399 is about 4611.1168929013. The cubic root of 21262399 is about 277.0367739107.

The spelling of 21262399 in words is "twenty-one million, two hundred sixty-two thousand, three hundred ninety-nine".