81770290 has 32 divisors (see below), whose sum is σ = 175530240. Its totient is φ = 26816064.

The previous prime is 81770287. The next prime is 81770329. The reversal of 81770290 is 9207718.

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 15 ways as a sum of consecutive naturals, for example, 23785 + ... + 27004.

It is an arithmetic number, because the mean of its divisors is an integer number (5485320).

Almost surely, 2^81770290 is an apocalyptic number.

81770290 is an abundant number, since it is smaller than the sum of its proper divisors (93759950).

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

81770290 is a wasteful number, since it uses less digits than its factorization.

81770290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50826.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 81770290 is about 9042.6926299637. The cubic root of 81770290 is about 434.0420899668.

The spelling of 81770290 in words is "eighty-one million, seven hundred seventy thousand, two hundred ninety".