21552623 has 2 divisors, whose sum is σ = 21552624. Its totient is φ = 21552622.

The previous prime is 21552613. The next prime is 21552637. The reversal of 21552623 is 32625512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21552623 - 2⁴ = 21552607 is a prime.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 21552592 and 21552601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21552613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10776311 + 10776312.

It is an arithmetic number, because the mean of its divisors is an integer number (10776312).

Almost surely, 2^21552623 is an apocalyptic number.

21552623 is a deficient number, since it is larger than the sum of its proper divisors (1).

21552623 is an equidigital number, since it uses as much as digits as its factorization.

21552623 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3600, while the sum is 26.

The square root of 21552623 is about 4642.4802638245. The cubic root of 21552623 is about 278.2915656386.

It can be divided in two parts, 2155 and 2623, that multiplied together give a palindrome (5652565).

The spelling of 21552623 in words is "twenty-one million, five hundred fifty-two thousand, six hundred twenty-three".