21265390 has 8 divisors (see below), whose sum is σ = 38277720. Its totient is φ = 8506152.

The previous prime is 21265373. The next prime is 21265397. The reversal of 21265390 is 9356212.

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

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21265397) 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, 1063260 + ... + 1063279.

It is an arithmetic number, because the mean of its divisors is an integer number (4784715).

Almost surely, 2^21265390 is an apocalyptic number.

21265390 is a deficient number, since it is larger than the sum of its proper divisors (17012330).

21265390 is a wasteful number, since it uses less digits than its factorization.

21265390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2126546.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 21265390 is about 4611.4412063909. The cubic root of 21265390 is about 277.0497636355.

The spelling of 21265390 in words is "twenty-one million, two hundred sixty-five thousand, three hundred ninety".