21265969 has 6 divisors (see below), whose sum is σ = 21975090. Its totient is φ = 20579040.

The previous prime is 21265967. The next prime is 21265999. The reversal of 21265969 is 96956212.

It can be written as a sum of positive squares in only one way, i.e., 21049744 + 216225 = 4588^2 + 465^2 .

It is not a de Polignac number, because 21265969 - 2¹ = 21265967 is a prime.

It is a super-2 number, since 2×21265969² = 904482875017922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21265967) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10104 + ... + 12025.

It is an arithmetic number, because the mean of its divisors is an integer number (3662515).

Almost surely, 2^21265969 is an apocalyptic number.

It is an amenable number.

21265969 is a deficient number, since it is larger than the sum of its proper divisors (709121).

21265969 is an equidigital number, since it uses as much as digits as its factorization.

21265969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22191 (or 22160 counting only the distinct ones).

The product of its digits is 58320, while the sum is 40.

The square root of 21265969 is about 4611.5039846020. The cubic root of 21265969 is about 277.0522780554.

The spelling of 21265969 in words is "twenty-one million, two hundred sixty-five thousand, nine hundred sixty-nine".