81877818 has 32 divisors (see below), whose sum is σ = 183476160. Its totient is φ = 24140160.

The previous prime is 81877813. The next prime is 81877823.

It is a happy number.

81877818 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (81877813) and next prime (81877823).

It is a super-2 number, since 2×81877818² = 13407954160882248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81877813) 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, 14323 + ... + 19206.

It is an arithmetic number, because the mean of its divisors is an integer number (5733630).

Almost surely, 2^81877818 is an apocalyptic number.

81877818 is an abundant number, since it is smaller than the sum of its proper divisors (101598342).

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

81877818 is a wasteful number, since it uses less digits than its factorization.

81877818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33582.

The product of its digits is 200704, while the sum is 48.

The square root of 81877818 is about 9048.6362508391. The cubic root of 81877818 is about 434.2322618700.

The spelling of 81877818 in words is "eighty-one million, eight hundred seventy-seven thousand, eight hundred eighteen".