21363623 has 4 divisors (see below), whose sum is σ = 21459648. Its totient is φ = 21267600.

The previous prime is 21363613. The next prime is 21363637. The reversal of 21363623 is 32636312.

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 21363623 - 2⁴ = 21363607 is a prime.

It is a super-2 number, since 2×21363623² = 912808775372258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21363592 and 21363601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21363613) 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, 47678 + ... + 48123.

It is an arithmetic number, because the mean of its divisors is an integer number (5364912).

Almost surely, 2^21363623 is an apocalyptic number.

21363623 is a deficient number, since it is larger than the sum of its proper divisors (96025).

21363623 is an equidigital number, since it uses as much as digits as its factorization.

21363623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96024.

The product of its digits is 3888, while the sum is 26.

The square root of 21363623 is about 4622.0799430559. The cubic root of 21363623 is about 277.4757081785.

Adding to 21363623 its reverse (32636312), we get a palindrome (53999935).

It can be divided in two parts, 213 and 63623, that added together give a palindrome (63836).

The spelling of 21363623 in words is "twenty-one million, three hundred sixty-three thousand, six hundred twenty-three".