21612423 has 16 divisors (see below), whose sum is σ = 34871040. Its totient is φ = 11623296.

The previous prime is 21612413. The next prime is 21612431. The reversal of 21612423 is 32421612.

It is not a de Polignac number, because 21612423 - 2¹⁶ = 21546887 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21612423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21612413) 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 15 ways as a sum of consecutive naturals, for example, 29913 + ... + 30626.

It is an arithmetic number, because the mean of its divisors is an integer number (2179440).

Almost surely, 2^21612423 is an apocalyptic number.

21612423 is a deficient number, since it is larger than the sum of its proper divisors (13258617).

21612423 is a wasteful number, since it uses less digits than its factorization.

21612423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60566.

The product of its digits is 576, while the sum is 21.

The square root of 21612423 is about 4648.9163253386. The cubic root of 21612423 is about 278.5487109491.

The spelling of 21612423 in words is "twenty-one million, six hundred twelve thousand, four hundred twenty-three".