81761740 has 12 divisors (see below), whose sum is σ = 171699696. Its totient is φ = 32704688.

The previous prime is 81761699. The next prime is 81761767. The reversal of 81761740 is 4716718.

It is a junction number, because it is equal to n+sod(n) for n = 81761696 and 81761705.

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, 2044024 + ... + 2044063.

It is an arithmetic number, because the mean of its divisors is an integer number (14308308).

Almost surely, 2^81761740 is an apocalyptic number.

It is an amenable number.

81761740 is an abundant number, since it is smaller than the sum of its proper divisors (89937956).

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

81761740 is a wasteful number, since it uses less digits than its factorization.

81761740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4088096 (or 4088094 counting only the distinct ones).

The product of its (nonzero) digits is 9408, while the sum is 34.

The square root of 81761740 is about 9042.2198601892. The cubic root of 81761740 is about 434.0269614516.

The spelling of 81761740 in words is "eighty-one million, seven hundred sixty-one thousand, seven hundred forty".