21481623 has 12 divisors (see below), whose sum is σ = 31202808. Its totient is φ = 14240880.

The previous prime is 21481613. The next prime is 21481631. The reversal of 21481623 is 32618412.

It is not a de Polignac number, because 21481623 - 2⁹ = 21481111 is a prime.

It is a super-2 number, since 2×21481623² = 922920253428258, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21481613) 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 11 ways as a sum of consecutive naturals, for example, 4965 + ... + 8222.

It is an arithmetic number, because the mean of its divisors is an integer number (2600234).

Almost surely, 2^21481623 is an apocalyptic number.

21481623 is a deficient number, since it is larger than the sum of its proper divisors (9721185).

21481623 is a wasteful number, since it uses less digits than its factorization.

21481623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13374 (or 13371 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21481623 is about 4634.8271812442. The cubic root of 21481623 is about 277.9856409608.

The spelling of 21481623 in words is "twenty-one million, four hundred eighty-one thousand, six hundred twenty-three".