81362880 has 280 divisors, whose sum is σ = 300209712. Its totient is φ = 20901888.

The previous prime is 81362861. The next prime is 81362899. The reversal of 81362880 is 8826318.

It is an interprime number because it is at equal distance from previous prime (81362861) and next prime (81362899).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1114524 + ... + 1114596.

Almost surely, 2^81362880 is an apocalyptic number.

81362880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81362880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150104856).

81362880 is an abundant number, since it is smaller than the sum of its proper divisors (218846832).

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

81362880 is a wasteful number, since it uses less digits than its factorization.

81362880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145 (or 126 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 81362880 is about 9020.1374712362. The cubic root of 81362880 is about 433.3200364099.

The spelling of 81362880 in words is "eighty-one million, three hundred sixty-two thousand, eight hundred eighty".