21451996225 has 27 divisors (see below), whose sum is σ = 29249522659. Its totient is φ = 15595593200.

The previous prime is 21451996183. The next prime is 21451996243. The reversal of 21451996225 is 52269915412.

The square root of 21451996225 is 146465.

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

It can be written as a sum of positive squares in only one way, i.e., 7722718641 + 13729277584 = 87879^2 + 117172^2 .

It is not a de Polignac number, because 21451996225 - 2²³ = 21443607617 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 8054244 + ... + 8056906.

Almost surely, 2^21451996225 is an apocalyptic number.

21451996225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21451996225 is the 146465-th square number.

21451996225 is the 73233-rd centered octagonal number.

It is an amenable number.

21451996225 is a deficient number, since it is larger than the sum of its proper divisors (7797526434).

21451996225 is an frugal number, since it uses more digits than its factorization.

21451996225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5358 (or 2679 counting only the distinct ones).

The product of its digits is 388800, while the sum is 46.

The spelling of 21451996225 in words is "twenty-one billion, four hundred fifty-one million, nine hundred ninety-six thousand, two hundred twenty-five".