21123044 has 24 divisors (see below), whose sum is σ = 39885048. Its totient is φ = 9751040.

The previous prime is 21123043. The next prime is 21123073. The reversal of 21123044 is 44032112.

It can be written as a sum of positive squares in 4 ways, for example, as 7344100 + 13778944 = 2710^2 + 3712^2 .

It is a Harshad number since it is a multiple of its sum of digits (17).

It is not an unprimeable number, because it can be changed into a prime (21123043) 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, 674 + ... + 6534.

It is an arithmetic number, because the mean of its divisors is an integer number (1661877).

Almost surely, 2^21123044 is an apocalyptic number.

It is an amenable number.

21123044 is a deficient number, since it is larger than the sum of its proper divisors (18762004).

21123044 is a wasteful number, since it uses less digits than its factorization.

21123044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5935 (or 5933 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21123044 is about 4595.9812880385. The cubic root of 21123044 is about 276.4302084415.

Adding to 21123044 its reverse (44032112), we get a palindrome (65155156).

The spelling of 21123044 in words is "twenty-one million, one hundred twenty-three thousand, forty-four".