81351880 has 16 divisors (see below), whose sum is σ = 183041820. Its totient is φ = 32540736.

The previous prime is 81351847. The next prime is 81351883. The reversal of 81351880 is 8815318.

It can be written as a sum of positive squares in 2 ways, for example, as 81324324 + 27556 = 9018^2 + 166^2 .

It is not an unprimeable number, because it can be changed into a prime (81351883) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1016859 + ... + 1016938.

Almost surely, 2^81351880 is an apocalyptic number.

It is an amenable number.

81351880 is an abundant number, since it is smaller than the sum of its proper divisors (101689940).

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

81351880 is a wasteful number, since it uses less digits than its factorization.

81351880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2033808 (or 2033804 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 34.

The square root of 81351880 is about 9019.5277038213. The cubic root of 81351880 is about 433.3005077041.

The spelling of 81351880 in words is "eighty-one million, three hundred fifty-one thousand, eight hundred eighty".