81726880 has 24 divisors (see below), whose sum is σ = 193080132. Its totient is φ = 32690688.

The previous prime is 81726851. The next prime is 81726907. The reversal of 81726880 is 8862718.

It can be written as a sum of positive squares in 2 ways, for example, as 80353296 + 1373584 = 8964^2 + 1172^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its 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 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, 255237 + ... + 255556.

Almost surely, 2^81726880 is an apocalyptic number.

81726880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81726880 is an abundant number, since it is smaller than the sum of its proper divisors (111353252).

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

81726880 is a wasteful number, since it uses less digits than its factorization.

81726880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510808 (or 510800 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 40.

The square root of 81726880 is about 9040.2920306813. The cubic root of 81726880 is about 433.9652686570.

The spelling of 81726880 in words is "eighty-one million, seven hundred twenty-six thousand, eight hundred eighty".