21255969 has 8 divisors (see below), whose sum is σ = 32390080. Its totient is φ = 12146256.

The previous prime is 21255947. The next prime is 21255973. The reversal of 21255969 is 96955212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21255969 - 2¹² = 21251873 is a prime.

It is a super-2 number, since 2×21255969² = 903632436257922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21255919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 506074 + ... + 506115.

It is an arithmetic number, because the mean of its divisors is an integer number (4048760).

Almost surely, 2^21255969 is an apocalyptic number.

It is an amenable number.

21255969 is a deficient number, since it is larger than the sum of its proper divisors (11134111).

21255969 is a wasteful number, since it uses less digits than its factorization.

21255969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1012199.

The product of its digits is 48600, while the sum is 39.

The square root of 21255969 is about 4610.4196121394. The cubic root of 21255969 is about 277.0088447001.

The spelling of 21255969 in words is "twenty-one million, two hundred fifty-five thousand, nine hundred sixty-nine".