81373280 has 24 divisors (see below), whose sum is σ = 192244752. Its totient is φ = 32549248.

The previous prime is 81373267. The next prime is 81373297. The reversal of 81373280 is 8237318.

It is a super-2 number, since 2×81373280² = 13243221395916800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 254132 + ... + 254451.

It is an arithmetic number, because the mean of its divisors is an integer number (8010198).

Almost surely, 2^81373280 is an apocalyptic number.

81373280 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81373280 is an abundant number, since it is smaller than the sum of its proper divisors (110871472).

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

81373280 is a wasteful number, since it uses less digits than its factorization.

81373280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508598 (or 508590 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 81373280 is about 9020.7139407034. The cubic root of 81373280 is about 433.3384982948.

The spelling of 81373280 in words is "eighty-one million, three hundred seventy-three thousand, two hundred eighty".