81868620 has 24 divisors (see below), whose sum is σ = 229232304. Its totient is φ = 21831616.

The previous prime is 81868601. The next prime is 81868639. The reversal of 81868620 is 2686818.

It is an interprime number because it is at equal distance from previous prime (81868601) and next prime (81868639).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 682179 + ... + 682298.

It is an arithmetic number, because the mean of its divisors is an integer number (9551346).

Almost surely, 2^81868620 is an apocalyptic number.

It is an amenable number.

81868620 is an abundant number, since it is smaller than the sum of its proper divisors (147363684).

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

81868620 is a wasteful number, since it uses less digits than its factorization.

81868620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1364489 (or 1364487 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 39.

The square root of 81868620 is about 9048.1279831797. The cubic root of 81868620 is about 434.2160009826.

The spelling of 81868620 in words is "eighty-one million, eight hundred sixty-eight thousand, six hundred twenty".