21407275 has 12 divisors (see below), whose sum is σ = 27263632. Its totient is φ = 16662240.

The previous prime is 21407263. The next prime is 21407293. The reversal of 21407275 is 57270412.

It is a de Polignac number, because none of the positive numbers 2^k-21407275 is a prime.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10647 + ... + 12496.

Almost surely, 2^21407275 is an apocalyptic number.

21407275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21407275 is a deficient number, since it is larger than the sum of its proper divisors (5856357).

21407275 is a wasteful number, since it uses less digits than its factorization.

21407275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23190 (or 23185 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 28.

The square root of 21407275 is about 4626.7996498660. The cubic root of 21407275 is about 277.6645670514.

Adding to 21407275 its reverse (57270412), we get a palindrome (78677687).

The spelling of 21407275 in words is "twenty-one million, four hundred seven thousand, two hundred seventy-five".