81391166430 has 64 divisors (see below), whose sum is σ = 225545886720. Its totient is φ = 18411899904.

The previous prime is 81391166401. The next prime is 81391166453. The reversal of 81391166430 is 3466119318.

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 1977450 + ... + 2018189.

It is an arithmetic number, because the mean of its divisors is an integer number (3524154480).

Almost surely, 2^81391166430 is an apocalyptic number.

81391166430 is an abundant number, since it is smaller than the sum of its proper divisors (144154720290).

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

81391166430 is a wasteful number, since it uses less digits than its factorization.

81391166430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3995753.

The product of its (nonzero) digits is 93312, while the sum is 42.

The spelling of 81391166430 in words is "eighty-one billion, three hundred ninety-one million, one hundred sixty-six thousand, four hundred thirty".