21044457 has 24 divisors (see below), whose sum is σ = 36570560. Its totient is φ = 11391840.

The previous prime is 21044431. The next prime is 21044467. The reversal of 21044457 is 75444012.

21044457 is a `hidden beast` number, since 210 + 4 + 445 + 7 = 666.

It is not a de Polignac number, because 21044457 - 2²⁰ = 19995881 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21044457.

It is not an unprimeable number, because it can be changed into a prime (21044407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7594 + ... + 9987.

Almost surely, 2^21044457 is an apocalyptic number.

It is an amenable number.

21044457 is a deficient number, since it is larger than the sum of its proper divisors (15526103).

21044457 is a wasteful number, since it uses less digits than its factorization.

21044457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17613 (or 17610 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 27.

The square root of 21044457 is about 4587.4237868329. The cubic root of 21044457 is about 276.0869684973.

Adding to 21044457 its reverse (75444012), we get a palindrome (96488469).

It can be divided in two parts, 2104 and 4457, that added together give a 8-th power (6561 = 3⁸).

The spelling of 21044457 in words is "twenty-one million, forty-four thousand, four hundred fifty-seven".