816644929 has 15 divisors (see below), whose sum is σ = 889196335. Its totient is φ = 749860480.

The previous prime is 816644903. The next prime is 816644951. The reversal of 816644929 is 929446618.

The square root of 816644929 is 28577.

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

It can be written as a sum of positive squares in 7 ways, for example, as 814817025 + 1827904 = 28545^2 + 1352^2 .

It is not a de Polignac number, because 816644929 - 2²⁹ = 279774017 is a prime.

It is a super-2 number, since 2×816644929² = 1333817880122830082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816644989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 19918149 + ... + 19918189.

Almost surely, 2^816644929 is an apocalyptic number.

816644929 is the 28577-th square number.

816644929 is the 14289-th centered octagonal number.

It is an amenable number.

816644929 is a deficient number, since it is larger than the sum of its proper divisors (72551406).

816644929 is an frugal number, since it uses more digits than its factorization.

816644929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198 (or 58 counting only the distinct ones).

The product of its digits is 746496, while the sum is 49.

The cubic root of 816644929 is about 934.7118671400.

Multiplying 816644929 by its sum of digits (49), we get a square (40015601521 = 200039²).

Multiplying 816644929 by its product of digits (746496), we get a square (609622172918784 = 24690528²).

The spelling of 816644929 in words is "eight hundred sixteen million, six hundred forty-four thousand, nine hundred twenty-nine".