81797040 has 200 divisors, whose sum is σ = 306261648. Its totient is φ = 20113920.

The previous prime is 81797029. The next prime is 81797063. The reversal of 81797040 is 4079718.

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 = 81796986 and 81797004.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 83755 + ... + 84725.

Almost surely, 2^81797040 is an apocalyptic number.

81797040 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 81797040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153130824).

81797040 is an abundant number, since it is smaller than the sum of its proper divisors (224464608).

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

81797040 is a wasteful number, since it uses less digits than its factorization.

81797040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1009 (or 994 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 81797040 is about 9044.1716038563. The cubic root of 81797040 is about 434.0894150611.

The spelling of 81797040 in words is "eighty-one million, seven hundred ninety-seven thousand, forty".