81491154320 has 40 divisors (see below), whose sum is σ = 189481830720. Its totient is φ = 32593898880.

The previous prime is 81491154319. The next prime is 81491154323. The reversal of 81491154320 is 2345119418.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (81491154323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1236605 + ... + 1300835.

It is an arithmetic number, because the mean of its divisors is an integer number (4737045768).

Almost surely, 2^81491154320 is an apocalyptic number.

81491154320 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81491154320 is an abundant number, since it is smaller than the sum of its proper divisors (107990676400).

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

81491154320 is a wasteful number, since it uses less digits than its factorization.

81491154320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80103 (or 80097 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 38.

The spelling of 81491154320 in words is "eighty-one billion, four hundred ninety-one million, one hundred fifty-four thousand, three hundred twenty".