21273969 has 4 divisors (see below), whose sum is σ = 28365296. Its totient is φ = 14182644.

The previous prime is 21273961. The next prime is 21273991. The reversal of 21273969 is 96937212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21273969 - 2³ = 21273961 is a prime.

It is a super-2 number, since 2×21273969² = 905163514025922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21273961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3545659 + ... + 3545664.

It is an arithmetic number, because the mean of its divisors is an integer number (7091324).

Almost surely, 2^21273969 is an apocalyptic number.

It is an amenable number.

21273969 is a deficient number, since it is larger than the sum of its proper divisors (7091327).

21273969 is an equidigital number, since it uses as much as digits as its factorization.

21273969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7091326.

The product of its digits is 40824, while the sum is 39.

The square root of 21273969 is about 4612.3712990175. The cubic root of 21273969 is about 277.0870149372.

The spelling of 21273969 in words is "twenty-one million, two hundred seventy-three thousand, nine hundred sixty-nine".