816721725 has 12 divisors (see below), whose sum is σ = 1350313376. Its totient is φ = 435584880.

The previous prime is 816721721. The next prime is 816721729. The reversal of 816721725 is 527127618.

It is an interprime number because it is at equal distance from previous prime (816721721) and next prime (816721729).

It is not a de Polignac number, because 816721725 - 2² = 816721721 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816721721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5444737 + ... + 5444886.

Almost surely, 2^816721725 is an apocalyptic number.

It is an amenable number.

816721725 is a deficient number, since it is larger than the sum of its proper divisors (533591651).

816721725 is a wasteful number, since it uses less digits than its factorization.

816721725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10889636 (or 10889631 counting only the distinct ones).

The product of its digits is 47040, while the sum is 39.

The square root of 816721725 is about 28578.3436363971. The cubic root of 816721725 is about 934.7411658311.

It can be divided in two parts, 8167 and 21725, that added together give a palindrome (29892).

The spelling of 816721725 in words is "eight hundred sixteen million, seven hundred twenty-one thousand, seven hundred twenty-five".