821375136 has 72 divisors (see below), whose sum is σ = 2398946004. Its totient is φ = 266388480.

The previous prime is 821375131. The next prime is 821375171. The reversal of 821375136 is 631573128.

821375136 is a `hidden beast` number, since 8 + 2 + 137 + 513 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 770395536 + 50979600 = 27756^2 + 7140^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×821375136² = 1349314228078036992, which contains 22 as substring.

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 821375136.

It is not an unprimeable number, because it can be changed into a prime (821375131) 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, 27885 + ... + 49196.

Almost surely, 2^821375136 is an apocalyptic number.

It is an amenable number.

821375136 is an abundant number, since it is smaller than the sum of its proper divisors (1577570868).

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

821375136 is a wasteful number, since it uses less digits than its factorization.

821375136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77134 (or 77123 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The square root of 821375136 is about 28659.6429845174. The cubic root of 821375136 is about 936.5130870877.

The spelling of 821375136 in words is "eight hundred twenty-one million, three hundred seventy-five thousand, one hundred thirty-six".