21222744444225 has 27 divisors (see below), whose sum is σ = 38012417152489. Its totient is φ = 11318760182400.

The previous prime is 21222744444203. The next prime is 21222744444233. The reversal of 21222744444225 is 52244444722212.

The square root of 21222744444225 is 4606815.

It is a perfect power (a square), and thus also a powerful number.

21222744444225 is a `hidden beast` number, since 2 + 122 + 27 + 4 + 44 + 442 + 25 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1281625503921 + 19941118940304 = 1132089^2 + 4465548^2 .

It is not a de Polignac number, because 21222744444225 - 2¹⁵ = 21222744411457 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 68948665 + ... + 69255785.

Almost surely, 2^{21222744444225} is an apocalyptic number.

21222744444225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21222744444225 is the 4606815-th square number.

21222744444225 is the 2303408-th centered octagonal number.

It is an amenable number.

21222744444225 is a deficient number, since it is larger than the sum of its proper divisors (16789672708264).

21222744444225 is an frugal number, since it uses more digits than its factorization.

21222744444225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614258 (or 307129 counting only the distinct ones).

The product of its digits is 2293760, while the sum is 45.

The spelling of 21222744444225 in words is "twenty-one trillion, two hundred twenty-two billion, seven hundred forty-four million, four hundred forty-four thousand, two hundred twenty-five".