21457275 has 48 divisors (see below), whose sum is σ = 42330624. Its totient is φ = 9377280.

The previous prime is 21457253. The next prime is 21457279. The reversal of 21457275 is 57275412.

It is not a de Polignac number, because 21457275 - 2¹⁰ = 21456251 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21457279) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11187 + ... + 12963.

It is an arithmetic number, because the mean of its divisors is an integer number (881888).

Almost surely, 2^21457275 is an apocalyptic number.

21457275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21457275 is a deficient number, since it is larger than the sum of its proper divisors (20873349).

21457275 is a wasteful number, since it uses less digits than its factorization.

21457275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1820 (or 1815 counting only the distinct ones).

The product of its digits is 19600, while the sum is 33.

The square root of 21457275 is about 4632.1998013903. The cubic root of 21457275 is about 277.8805751382.

The spelling of 21457275 in words is "twenty-one million, four hundred fifty-seven thousand, two hundred seventy-five".