81492840 has 192 divisors, whose sum is σ = 311351040. Its totient is φ = 18224640.

The previous prime is 81492823. The next prime is 81492857. The reversal of 81492840 is 4829418.

It is an interprime number because it is at equal distance from previous prime (81492823) and next prime (81492857).

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

It is a junction number, because it is equal to n+sod(n) for n = 81492795 and 81492804.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 50689 + ... + 52271.

It is an arithmetic number, because the mean of its divisors is an integer number (1621620).

Almost surely, 2^81492840 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 81492840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155675520).

81492840 is an abundant number, since it is smaller than the sum of its proper divisors (229858200).

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

81492840 is a wasteful number, since it uses less digits than its factorization.

81492840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1624 (or 1617 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 81492840 is about 9027.3384782005. The cubic root of 81492840 is about 433.5506260642.

The spelling of 81492840 in words is "eighty-one million, four hundred ninety-two thousand, eight hundred forty".