81475760 has 20 divisors (see below), whose sum is σ = 189431328. Its totient is φ = 32590272.

The previous prime is 81475759. The next prime is 81475763. The reversal of 81475760 is 6757418.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81475763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 509144 + ... + 509303.

Almost surely, 2^81475760 is an apocalyptic number.

81475760 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81475760 is an abundant number, since it is smaller than the sum of its proper divisors (107955568).

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

81475760 is a wasteful number, since it uses less digits than its factorization.

81475760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018460 (or 1018454 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 38.

The square root of 81475760 is about 9026.3924133621. The cubic root of 81475760 is about 433.5203348055.

The spelling of 81475760 in words is "eighty-one million, four hundred seventy-five thousand, seven hundred sixty".