81492880 has 60 divisors (see below), whose sum is σ = 220415580. Its totient is φ = 27939072.

The previous prime is 81492863. The next prime is 81492911. The reversal of 81492880 is 8829418.

It can be written as a sum of positive squares in 2 ways, for example, as 52591504 + 28901376 = 7252^2 + 5376^2 .

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6475 + ... + 14314.

It is an arithmetic number, because the mean of its divisors is an integer number (3673593).

Almost surely, 2^81492880 is an apocalyptic number.

81492880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81492880 is an abundant number, since it is smaller than the sum of its proper divisors (138922700).

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

81492880 is a wasteful number, since it uses less digits than its factorization.

81492880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20816 (or 20803 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 40.

The square root of 81492880 is about 9027.3406936927. The cubic root of 81492880 is about 433.5506969990.

The spelling of 81492880 in words is "eighty-one million, four hundred ninety-two thousand, eight hundred eighty".