21265651 has 8 divisors (see below), whose sum is σ = 23429808. Its totient is φ = 19140000.

The previous prime is 21265633. The next prime is 21265661. The reversal of 21265651 is 15656212.

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

It is not a de Polignac number, because 21265651 - 2⁵ = 21265619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21265631) 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, 8460 + ... + 10681.

It is an arithmetic number, because the mean of its divisors is an integer number (2928726).

Almost surely, 2^21265651 is an apocalyptic number.

21265651 is a deficient number, since it is larger than the sum of its proper divisors (2164157).

21265651 is a wasteful number, since it uses less digits than its factorization.

21265651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19253.

The product of its digits is 3600, while the sum is 28.

The square root of 21265651 is about 4611.4695054830. The cubic root of 21265651 is about 277.0508970843.

It can be divided in two parts, 2126 and 5651, that added together give a palindrome (7777).

The spelling of 21265651 in words is "twenty-one million, two hundred sixty-five thousand, six hundred fifty-one".