866827614021820 has 48 divisors (see below), whose sum is σ = 1985828394848256. Its totient is φ = 315209226600000.

The previous prime is 866827614021773. The next prime is 866827614021821. The reversal of 866827614021820 is 28120416728668.

It is a happy number.

It is a super-2 number, since 2×866827614021820² (a number of 31 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (61) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866827614021821) 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, 83713705 + ... + 93496735.

It is an arithmetic number, because the mean of its divisors is an integer number (41371424892672).

Almost surely, 2^{866827614021820} is an apocalyptic number.

It is an amenable number.

866827614021820 is an abundant number, since it is smaller than the sum of its proper divisors (1119000780826436).

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

866827614021820 is a wasteful number, since it uses less digits than its factorization.

866827614021820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10185802 (or 10185800 counting only the distinct ones).

The product of its (nonzero) digits is 24772608, while the sum is 61.

The spelling of 866827614021820 in words is "eight hundred sixty-six trillion, eight hundred twenty-seven billion, six hundred fourteen million, twenty-one thousand, eight hundred twenty".