21996838225 has 6 divisors (see below), whose sum is σ = 27276079430. Its totient is φ = 17597470560.

The previous prime is 21996838207. The next prime is 21996838247. The reversal of 21996838225 is 52283869912.

It can be written as a sum of positive squares in 3 ways, for example, as 377252929 + 21619585296 = 19423^2 + 147036^2 .

It is not a de Polignac number, because 21996838225 - 2²¹ = 21994741073 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 439936740 + ... + 439936789.

Almost surely, 2^21996838225 is an apocalyptic number.

21996838225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21996838225 is a deficient number, since it is larger than the sum of its proper divisors (5279241205).

21996838225 is an equidigital number, since it uses as much as digits as its factorization.

21996838225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 879873539 (or 879873534 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 55.

The spelling of 21996838225 in words is "twenty-one billion, nine hundred ninety-six million, eight hundred thirty-eight thousand, two hundred twenty-five".