81192222720 has 1360 divisors, whose sum is σ = 365404976640. Its totient is φ = 16817061888.

The previous prime is 81192222703. The next prime is 81192222757. The reversal of 81192222720 is 2722229118.

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 79 ways as a sum of consecutive naturals, for example, 3530096629 + ... + 3530096651.

Almost surely, 2^81192222720 is an apocalyptic number.

81192222720 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 81192222720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (182702488320).

81192222720 is an abundant number, since it is smaller than the sum of its proper divisors (284212753920).

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

81192222720 is an equidigital number, since it uses as much as digits as its factorization.

81192222720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 59 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The spelling of 81192222720 in words is "eighty-one billion, one hundred ninety-two million, two hundred twenty-two thousand, seven hundred twenty".