91681540 has 12 divisors (see below), whose sum is σ = 192531276. Its totient is φ = 36672608.

The previous prime is 91681531. The next prime is 91681553. The reversal of 91681540 is 4518619.

It can be written as a sum of positive squares in 2 ways, for example, as 72863296 + 18818244 = 8536^2 + 4338^2 .

It is a junction number, because it is equal to n+sod(n) for n = 91681496 and 91681505.

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, 2292019 + ... + 2292058.

It is an arithmetic number, because the mean of its divisors is an integer number (16044273).

Almost surely, 2^91681540 is an apocalyptic number.

It is an amenable number.

91681540 is an abundant number, since it is smaller than the sum of its proper divisors (100849736).

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

91681540 is a wasteful number, since it uses less digits than its factorization.

91681540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4584086 (or 4584084 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 91681540 is about 9575.0477805596. The cubic root of 91681540 is about 450.9142564908.

The spelling of 91681540 in words is "ninety-one million, six hundred eighty-one thousand, five hundred forty".