16431394225 has 27 divisors (see below), whose sum is σ = 21078874731. Its totient is φ = 12705697200.

The previous prime is 16431394211. The next prime is 16431394241. The reversal of 16431394225 is 52249313461.

The square root of 16431394225 is 128185.

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., 5915301921 + 10516092304 = 76911^2 + 102548^2 .

It is a de Polignac number, because none of the positive numbers 2^k-16431394225 is a prime.

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, 19868262 + ... + 19869088.

Almost surely, 2^16431394225 is an apocalyptic number.

16431394225 is the 128185-th square number.

16431394225 is the 64093-rd centered octagonal number.

It is an amenable number.

16431394225 is a deficient number, since it is larger than the sum of its proper divisors (4647480506).

16431394225 is an frugal number, since it uses more digits than its factorization.

16431394225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1726 (or 863 counting only the distinct ones).

The product of its digits is 155520, while the sum is 40.

The spelling of 16431394225 in words is "sixteen billion, four hundred thirty-one million, three hundred ninety-four thousand, two hundred twenty-five".