816402639 has 16 divisors (see below), whose sum is σ = 1210087424. Its totient is φ = 486194400.

The previous prime is 816402637. The next prime is 816402649. The reversal of 816402639 is 936204618.

It is not a de Polignac number, because 816402639 - 2¹ = 816402637 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 816402597 and 816402606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816402637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 336427 + ... + 338844.

It is an arithmetic number, because the mean of its divisors is an integer number (75630464).

Almost surely, 2^816402639 is an apocalyptic number.

816402639 is a deficient number, since it is larger than the sum of its proper divisors (393684785).

816402639 is a wasteful number, since it uses less digits than its factorization.

816402639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 675318.

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 816402639 is about 28572.7604371716. The cubic root of 816402639 is about 934.6194182550.

The spelling of 816402639 in words is "eight hundred sixteen million, four hundred two thousand, six hundred thirty-nine".