81770440 has 32 divisors (see below), whose sum is σ = 184637880. Its totient is φ = 32591872.

The previous prime is 81770419. The next prime is 81770489. The reversal of 81770440 is 4407718.

It can be written as a sum of positive squares in 4 ways, for example, as 72148036 + 9622404 = 8494^2 + 3102^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8232 + ... + 15208.

Almost surely, 2^81770440 is an apocalyptic number.

It is an amenable number.

81770440 is an abundant number, since it is smaller than the sum of its proper divisors (102867440).

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

81770440 is a wasteful number, since it uses less digits than its factorization.

81770440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7281 (or 7277 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 81770440 is about 9042.7009239497. The cubic root of 81770440 is about 434.0423553699.

The spelling of 81770440 in words is "eighty-one million, seven hundred seventy thousand, four hundred forty".