81373680 has 160 divisors (see below), whose sum is σ = 283821120. Its totient is φ = 21427200.

The previous prime is 81373657. The next prime is 81373697. The reversal of 81373680 is 8637318.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 217974 + ... + 218346.

It is an arithmetic number, because the mean of its divisors is an integer number (1773882).

Almost surely, 2^81373680 is an apocalyptic number.

81373680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81373680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141910560).

81373680 is an abundant number, since it is smaller than the sum of its proper divisors (202447440).

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

81373680 is a wasteful number, since it uses less digits than its factorization.

81373680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496 (or 484 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 81373680 is about 9020.7361118703. The cubic root of 81373680 is about 433.3392083359.

The spelling of 81373680 in words is "eighty-one million, three hundred seventy-three thousand, six hundred eighty".