16818199225 has 27 divisors (see below), whose sum is σ = 21464056551. Its totient is φ = 13072248000.

The previous prime is 16818199217. The next prime is 16818199231. The reversal of 16818199225 is 52299181861.

It is a happy number.

The square root of 16818199225 is 129685.

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

It can be written as a sum of positive squares in 13 ways, for example, as 74874409 + 16743324816 = 8653^2 + 129396^2 .

It is not a de Polignac number, because 16818199225 - 2³ = 16818199217 is a prime.

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, 23991375 + ... + 23992075.

Almost surely, 2^16818199225 is an apocalyptic number.

16818199225 is the 129685-th square number.

16818199225 is the 64843-rd centered octagonal number.

It is an amenable number.

16818199225 is a deficient number, since it is larger than the sum of its proper divisors (4645857326).

16818199225 is an frugal number, since it uses more digits than its factorization.

16818199225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486 (or 743 counting only the distinct ones).

The product of its digits is 622080, while the sum is 52.

The spelling of 16818199225 in words is "sixteen billion, eight hundred eighteen million, one hundred ninety-nine thousand, two hundred twenty-five".