81356790 has 32 divisors (see below), whose sum is σ = 195503616. Its totient is φ = 21667680.

The previous prime is 81356789. The next prime is 81356791. The reversal of 81356790 is 9765318.

It is an interprime number because it is at equal distance from previous prime (81356789) and next prime (81356791).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81356791) by changing a digit.

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, 35829 + ... + 38031.

It is an arithmetic number, because the mean of its divisors is an integer number (6109488).

Almost surely, 2^81356790 is an apocalyptic number.

81356790 is an abundant number, since it is smaller than the sum of its proper divisors (114146826).

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

81356790 is a wasteful number, since it uses less digits than its factorization.

81356790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3444.

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 81356790 is about 9019.7998869155. The cubic root of 81356790 is about 433.3092248257.

The spelling of 81356790 in words is "eighty-one million, three hundred fifty-six thousand, seven hundred ninety".