81870497280 has 1200 divisors, whose sum is σ = 348491726352. Its totient is φ = 18247680000.

The previous prime is 81870497263. The next prime is 81870497321. The reversal of 81870497280 is 8279407818.

It is a happy number.

81870497280 is a `hidden beast` number, since 8 + 1 + 8 + 70 + 497 + 2 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 326177155 + ... + 326177405.

Almost surely, 2^81870497280 is an apocalyptic number.

81870497280 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 81870497280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (174245863176).

81870497280 is an abundant number, since it is smaller than the sum of its proper divisors (266621229072).

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

81870497280 is a wasteful number, since it uses less digits than its factorization.

81870497280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321 (or 285 counting only the distinct ones).

The product of its (nonzero) digits is 1806336, while the sum is 54.

The spelling of 81870497280 in words is "eighty-one billion, eight hundred seventy million, four hundred ninety-seven thousand, two hundred eighty".