21297230 has 16 divisors (see below), whose sum is σ = 38985840. Its totient is φ = 8374272.

The previous prime is 21297203. The next prime is 21297247. The reversal of 21297230 is 3279212.

21297230 = T₈₂₀ + T₈₂₁ + ... + T₈₇₈.

It is a self number, because there is not a number n which added to its sum of digits gives 21297230.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17459 + ... + 18638.

It is an arithmetic number, because the mean of its divisors is an integer number (2436615).

Almost surely, 2^21297230 is an apocalyptic number.

21297230 is a deficient number, since it is larger than the sum of its proper divisors (17688610).

21297230 is a wasteful number, since it uses less digits than its factorization.

21297230 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36163.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21297230 is about 4614.8921980909. The cubic root of 21297230 is about 277.1879673166.

The spelling of 21297230 in words is "twenty-one million, two hundred ninety-seven thousand, two hundred thirty".