21275242 has 4 divisors (see below), whose sum is σ = 31912866. Its totient is φ = 10637620.

The previous prime is 21275237. The next prime is 21275281. The reversal of 21275242 is 24257212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19175641 + 2099601 = 4379^2 + 1449^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5318809 + ... + 5318812.

Almost surely, 2^21275242 is an apocalyptic number.

21275242 is a deficient number, since it is larger than the sum of its proper divisors (10637624).

21275242 is a wasteful number, since it uses less digits than its factorization.

21275242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10637623.

The product of its digits is 2240, while the sum is 25.

The square root of 21275242 is about 4612.5092953836. The cubic root of 21275242 is about 277.0925416403.

The spelling of 21275242 in words is "twenty-one million, two hundred seventy-five thousand, two hundred forty-two".