21252379 has 4 divisors (see below), whose sum is σ = 21363840. Its totient is φ = 21140920.

The previous prime is 21252377. The next prime is 21252383. The reversal of 21252379 is 97325212.

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

It is a cyclic number.

It is not a de Polignac number, because 21252379 - 2¹ = 21252377 is a prime.

It is a super-2 number, since 2×21252379² = 903327226319282, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21252379.

It is not an unprimeable number, because it can be changed into a prime (21252373) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55444 + ... + 55825.

It is an arithmetic number, because the mean of its divisors is an integer number (5340960).

Almost surely, 2^21252379 is an apocalyptic number.

21252379 is a deficient number, since it is larger than the sum of its proper divisors (111461).

21252379 is a wasteful number, since it uses less digits than its factorization.

21252379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111460.

The product of its digits is 7560, while the sum is 31.

The square root of 21252379 is about 4610.0302602044. The cubic root of 21252379 is about 276.9932488026.

It can be divided in two parts, 21252 and 379, that multiplied together give a palindrome (8054508).

The spelling of 21252379 in words is "twenty-one million, two hundred fifty-two thousand, three hundred seventy-nine".