21799923 has 8 divisors (see below), whose sum is σ = 29120448. Its totient is φ = 14506344.

The previous prime is 21799901. The next prime is 21799937. The reversal of 21799923 is 32999712.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21799923 - 2¹⁷ = 21668851 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21799123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4765 + ... + 8142.

It is an arithmetic number, because the mean of its divisors is an integer number (3640056).

Almost surely, 2^21799923 is an apocalyptic number.

21799923 is a deficient number, since it is larger than the sum of its proper divisors (7320525).

21799923 is a wasteful number, since it uses less digits than its factorization.

21799923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13473.

The product of its digits is 61236, while the sum is 42.

The square root of 21799923 is about 4669.0387661702. The cubic root of 21799923 is about 279.3519152234.

It can be divided in two parts, 21799 and 923, that added together give a palindrome (22722).

The spelling of 21799923 in words is "twenty-one million, seven hundred ninety-nine thousand, nine hundred twenty-three".