21269959 has 2 divisors, whose sum is σ = 21269960. Its totient is φ = 21269958.

The previous prime is 21269957. The next prime is 21269971. The reversal of 21269959 is 95996212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21269959 - 2¹ = 21269957 is a prime.

It is a super-2 number, since 2×21269959² = 904822311723362, which contains 22 as substring.

Together with 21269957, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21269953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10634979 + 10634980.

It is an arithmetic number, because the mean of its divisors is an integer number (10634980).

Almost surely, 2^21269959 is an apocalyptic number.

21269959 is a deficient number, since it is larger than the sum of its proper divisors (1).

21269959 is an equidigital number, since it uses as much as digits as its factorization.

21269959 is an evil number, because the sum of its binary digits is even.

The product of its digits is 87480, while the sum is 43.

The square root of 21269959 is about 4611.9365780548. The cubic root of 21269959 is about 277.0696041639.

The spelling of 21269959 in words is "twenty-one million, two hundred sixty-nine thousand, nine hundred fifty-nine".