864633640 has 32 divisors (see below), whose sum is σ = 2095075080. Its totient is φ = 319249152.

The previous prime is 864633587. The next prime is 864633643. The reversal of 864633640 is 46336468.

It can be written as a sum of positive squares in 4 ways, for example, as 279090436 + 585543204 = 16706^2 + 24198^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 864633593 and 864633602.

It is not an unprimeable number, because it can be changed into a prime (864633643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 830859 + ... + 831898.

Almost surely, 2^864633640 is an apocalyptic number.

It is an amenable number.

864633640 is an abundant number, since it is smaller than the sum of its proper divisors (1230441440).

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

864633640 is a wasteful number, since it uses less digits than its factorization.

864633640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1662781 (or 1662777 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 40.

The square root of 864633640 is about 29404.6533732333. The cubic root of 864633640 is about 952.6734078048.

The spelling of 864633640 in words is "eight hundred sixty-four million, six hundred thirty-three thousand, six hundred forty".