81400680 has 256 divisors, whose sum is σ = 295488000. Its totient is φ = 19869696.

The previous prime is 81400679. The next prime is 81400681. The reversal of 81400680 is 8600418.

It is an interprime number because it is at equal distance from previous prime (81400679) and next prime (81400681).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81400681) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 720304 + ... + 720416.

It is an arithmetic number, because the mean of its divisors is an integer number (1154250).

Almost surely, 2^81400680 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 81400680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147744000).

81400680 is an abundant number, since it is smaller than the sum of its proper divisors (214087320).

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

81400680 is a wasteful number, since it uses less digits than its factorization.

81400680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185 (or 175 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 81400680 is about 9022.2325396766. The cubic root of 81400680 is about 433.3871307305.

The spelling of 81400680 in words is "eighty-one million, four hundred thousand, six hundred eighty".