81281845790 has 8 divisors (see below), whose sum is σ = 146307322440. Its totient is φ = 32512738312.

The previous prime is 81281845789. The next prime is 81281845817. The reversal of 81281845790 is 9754818218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4064092280 + ... + 4064092299.

It is an arithmetic number, because the mean of its divisors is an integer number (18288415305).

Almost surely, 2^81281845790 is an apocalyptic number.

81281845790 is a deficient number, since it is larger than the sum of its proper divisors (65025476650).

81281845790 is a wasteful number, since it uses less digits than its factorization.

81281845790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8128184586.

The product of its (nonzero) digits is 1290240, while the sum is 53.

The spelling of 81281845790 in words is "eighty-one billion, two hundred eighty-one million, eight hundred forty-five thousand, seven hundred ninety".