820140636 has 72 divisors (see below), whose sum is σ = 2242565136. Its totient is φ = 232592640.

The previous prime is 820140623. The next prime is 820140641. The reversal of 820140636 is 636041028.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 75466 + ... + 85646.

It is an arithmetic number, because the mean of its divisors is an integer number (31146738).

Almost surely, 2^820140636 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 820140636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1121282568).

820140636 is an abundant number, since it is smaller than the sum of its proper divisors (1422424500).

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

820140636 is a wasteful number, since it uses less digits than its factorization.

820140636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10339 (or 10330 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 820140636 is about 28638.0976323498. The cubic root of 820140636 is about 936.0436689758.

The spelling of 820140636 in words is "eight hundred twenty million, one hundred forty thousand, six hundred thirty-six".