81287094720 has 224 divisors, whose sum is σ = 280695562560. Its totient is φ = 19810713600.

The previous prime is 81287094701. The next prime is 81287094739. The reversal of 81287094720 is 2749078218.

It is an interprime number because it is at equal distance from previous prime (81287094701) and next prime (81287094739).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 81287094720.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1228236 + ... + 1292724.

It is an arithmetic number, because the mean of its divisors is an integer number (1253105190).

Almost surely, 2^81287094720 is an apocalyptic number.

81287094720 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 81287094720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140347781280).

81287094720 is an abundant number, since it is smaller than the sum of its proper divisors (199408467840).

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

81287094720 is a wasteful number, since it uses less digits than its factorization.

81287094720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64623 (or 64613 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 48.

The spelling of 81287094720 in words is "eighty-one billion, two hundred eighty-seven million, ninety-four thousand, seven hundred twenty".