21252758 has 4 divisors (see below), whose sum is σ = 31879140. Its totient is φ = 10626378.

The previous prime is 21252739. The next prime is 21252769. The reversal of 21252758 is 85725212.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5313188 + ... + 5313191.

It is an arithmetic number, because the mean of its divisors is an integer number (7969785).

Almost surely, 2^21252758 is an apocalyptic number.

21252758 is a deficient number, since it is larger than the sum of its proper divisors (10626382).

21252758 is a wasteful number, since it uses less digits than its factorization.

21252758 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10626381.

The product of its digits is 11200, while the sum is 32.

The square root of 21252758 is about 4610.0713660420. The cubic root of 21252758 is about 276.9948953605.

The spelling of 21252758 in words is "twenty-one million, two hundred fifty-two thousand, seven hundred fifty-eight".