21224043025 has 12 divisors (see below), whose sum is σ = 26420225292. Its totient is φ = 16913162240.

The previous prime is 21224043013. The next prime is 21224043031. The reversal of 21224043025 is 52034042212.

It can be written as a sum of positive squares in 6 ways, for example, as 5068870416 + 16155172609 = 71196^2 + 127103^2 .

It is not a de Polignac number, because 21224043025 - 2³¹ = 19076559377 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1645252 + ... + 1658101.

It is an arithmetic number, because the mean of its divisors is an integer number (2201685441).

Almost surely, 2^21224043025 is an apocalyptic number.

21224043025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21224043025 is a deficient number, since it is larger than the sum of its proper divisors (5196182267).

21224043025 is a wasteful number, since it uses less digits than its factorization.

21224043025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3303620 (or 3303615 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 25.

Adding to 21224043025 its reverse (52034042212), we get a palindrome (73258085237).

The spelling of 21224043025 in words is "twenty-one billion, two hundred twenty-four million, forty-three thousand, twenty-five".