21265630 has 16 divisors (see below), whose sum is σ = 38803824. Its totient is φ = 8389440.

The previous prime is 21265619. The next prime is 21265631. The reversal of 21265630 is 3656212.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 21265595 and 21265604.

It is a congruent 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, 13836 + ... + 15295.

It is an arithmetic number, because the mean of its divisors is an integer number (2425239).

Almost surely, 2^21265630 is an apocalyptic number.

21265630 is a deficient number, since it is larger than the sum of its proper divisors (17538194).

21265630 is a wasteful number, since it uses less digits than its factorization.

21265630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29211.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21265630 is about 4611.4672285510. The cubic root of 21265630 is about 277.0508058876.

The spelling of 21265630 in words is "twenty-one million, two hundred sixty-five thousand, six hundred thirty".