81790870 has 32 divisors (see below), whose sum is σ = 168708096. Its totient is φ = 27967200.

The previous prime is 81790867. The next prime is 81790873. The reversal of 81790870 is 7809718.

It is an interprime number because it is at equal distance from previous prime (81790867) and next prime (81790873).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81790873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28815 + ... + 31525.

It is an arithmetic number, because the mean of its divisors is an integer number (5272128).

Almost surely, 2^81790870 is an apocalyptic number.

81790870 is an abundant number, since it is smaller than the sum of its proper divisors (86917226).

81790870 is a wasteful number, since it uses less digits than its factorization.

81790870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3156.

The product of its (nonzero) digits is 28224, while the sum is 40.

The square root of 81790870 is about 9043.8304937676. The cubic root of 81790870 is about 434.0785002446.

The spelling of 81790870 in words is "eighty-one million, seven hundred ninety thousand, eight hundred seventy".