21052623 has 4 divisors (see below), whose sum is σ = 28070168. Its totient is φ = 14035080.

The previous prime is 21052621. The next prime is 21052643. The reversal of 21052623 is 32625012.

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

It is not a de Polignac number, because 21052623 - 2¹ = 21052621 is a prime.

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 21052623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21052621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3508768 + ... + 3508773.

It is an arithmetic number, because the mean of its divisors is an integer number (7017542).

Almost surely, 2^21052623 is an apocalyptic number.

21052623 is a deficient number, since it is larger than the sum of its proper divisors (7017545).

21052623 is an equidigital number, since it uses as much as digits as its factorization.

21052623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7017544.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21052623 is about 4588.3137425420. The cubic root of 21052623 is about 276.1226744100.

Adding to 21052623 its reverse (32625012), we get a palindrome (53677635).

The spelling of 21052623 in words is "twenty-one million, fifty-two thousand, six hundred twenty-three".