21275042 has 4 divisors (see below), whose sum is σ = 31912566. Its totient is φ = 10637520.

The previous prime is 21275039. The next prime is 21275053. The reversal of 21275042 is 24057212.

It is a happy number.

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., 16072081 + 5202961 = 4009^2 + 2281^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21274999 and 21275017.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5318759 + ... + 5318762.

Almost surely, 2^21275042 is an apocalyptic number.

21275042 is a deficient number, since it is larger than the sum of its proper divisors (10637524).

21275042 is a wasteful number, since it uses less digits than its factorization.

21275042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10637523.

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 21275042 is about 4612.4876151595. The cubic root of 21275042 is about 277.0916733591.

The spelling of 21275042 in words is "twenty-one million, two hundred seventy-five thousand, forty-two".