81351886 has 32 divisors (see below), whose sum is σ = 153591552. Its totient is φ = 31392960.

The previous prime is 81351883. The next prime is 81351899. The reversal of 81351886 is 68815318.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 14010 + ... + 18946.

It is an arithmetic number, because the mean of its divisors is an integer number (4799736).

Almost surely, 2^81351886 is an apocalyptic number.

81351886 is a deficient number, since it is larger than the sum of its proper divisors (72239666).

81351886 is a wasteful number, since it uses less digits than its factorization.

81351886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5064.

The product of its digits is 46080, while the sum is 40.

The square root of 81351886 is about 9019.5280364329. The cubic root of 81351886 is about 433.3005183566.

It can be divided in two parts, 813518 and 86, that added together give a square (813604 = 902²).

The spelling of 81351886 in words is "eighty-one million, three hundred fifty-one thousand, eight hundred eighty-six".