81798740 has 12 divisors (see below), whose sum is σ = 171777396. Its totient is φ = 32719488.

The previous prime is 81798709. The next prime is 81798757. The reversal of 81798740 is 4789718.

It can be written as a sum of positive squares in 2 ways, for example, as 13868176 + 67930564 = 3724^2 + 8242^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81798691 and 81798700.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2044949 + ... + 2044988.

It is an arithmetic number, because the mean of its divisors is an integer number (14314783).

Almost surely, 2^81798740 is an apocalyptic number.

It is an amenable number.

81798740 is an abundant number, since it is smaller than the sum of its proper divisors (89978656).

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

81798740 is a wasteful number, since it uses less digits than its factorization.

81798740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4089946 (or 4089944 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 81798740 is about 9044.2655865471. The cubic root of 81798740 is about 434.0924222884.

The spelling of 81798740 in words is "eighty-one million, seven hundred ninety-eight thousand, seven hundred forty".