21999044 has 6 divisors (see below), whose sum is σ = 38498334. Its totient is φ = 10999520.

The previous prime is 21999041. The next prime is 21999059. The reversal of 21999044 is 44099912.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20340100 + 1658944 = 4510^2 + 1288^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21998989 and 21999007.

It is not an unprimeable number, because it can be changed into a prime (21999041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2749877 + ... + 2749884.

It is an arithmetic number, because the mean of its divisors is an integer number (6416389).

Almost surely, 2^21999044 is an apocalyptic number.

It is an amenable number.

21999044 is a deficient number, since it is larger than the sum of its proper divisors (16499290).

21999044 is a wasteful number, since it uses less digits than its factorization.

21999044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5499765 (or 5499763 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 21999044 is about 4690.3138487739. The cubic root of 21999044 is about 280.1998742952.

The spelling of 21999044 in words is "twenty-one million, nine hundred ninety-nine thousand, forty-four".