21237275 has 12 divisors (see below), whose sum is σ = 26399352. Its totient is φ = 16947840.

The previous prime is 21237241. The next prime is 21237287. The reversal of 21237275 is 57273212.

It is not a de Polignac number, because 21237275 - 2¹⁰ = 21236251 is a prime.

It is a Duffinian number.

It is a congruent 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, 12899 + ... + 14451.

It is an arithmetic number, because the mean of its divisors is an integer number (2199946).

Almost surely, 2^21237275 is an apocalyptic number.

21237275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21237275 is a deficient number, since it is larger than the sum of its proper divisors (5162077).

21237275 is a wasteful number, since it uses less digits than its factorization.

21237275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2110 (or 2105 counting only the distinct ones).

The product of its digits is 5880, while the sum is 29.

The square root of 21237275 is about 4608.3918019196. The cubic root of 21237275 is about 276.9276138363.

It can be divided in two parts, 21237 and 275, that added together give a palindrome (21512).

The spelling of 21237275 in words is "twenty-one million, two hundred thirty-seven thousand, two hundred seventy-five".