817220736 has 96 divisors (see below), whose sum is σ = 2490029100. Its totient is φ = 256376832.

The previous prime is 817220717. The next prime is 817220737. The reversal of 817220736 is 637022718.

It can be written as a sum of positive squares in 2 ways, for example, as 803382336 + 13838400 = 28344^2 + 3720^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 817220736.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (817220737) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1281 + ... + 40448.

Almost surely, 2^817220736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 817220736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1245014550).

817220736 is an abundant number, since it is smaller than the sum of its proper divisors (1672808364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

817220736 is a wasteful number, since it uses less digits than its factorization.

817220736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41766 (or 41751 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The square root of 817220736 is about 28587.0728826860. The cubic root of 817220736 is about 934.9315004104.

The spelling of 817220736 in words is "eight hundred seventeen million, two hundred twenty thousand, seven hundred thirty-six".