81191303424 has 1728 divisors, whose sum is σ = 340016947200. Its totient is φ = 18811699200.

The previous prime is 81191303411. The next prime is 81191303437. The reversal of 81191303424 is 42430319118.

It is an interprime number because it is at equal distance from previous prime (81191303411) and next prime (81191303437).

It is a tau number, because it is divible by the number of its divisors (1728).

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

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2194359534 + ... + 2194359570.

Almost surely, 2^81191303424 is an apocalyptic number.

81191303424 is a gapful number since it is divisible by the number (84) 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 81191303424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170008473600).

81191303424 is an abundant number, since it is smaller than the sum of its proper divisors (258825643776).

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

81191303424 is a wasteful number, since it uses less digits than its factorization.

81191303424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The spelling of 81191303424 in words is "eighty-one billion, one hundred ninety-one million, three hundred three thousand, four hundred twenty-four".