81944197485 has 32 divisors (see below), whose sum is σ = 137070109440. Its totient is φ = 41803323584.

The previous prime is 81944197471. The next prime is 81944197523. The reversal of 81944197485 is 58479144918.

It is not a de Polignac number, because 81944197485 - 2¹⁴ = 81944181101 is a prime.

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, 41994 + ... + 407003.

It is an arithmetic number, because the mean of its divisors is an integer number (4283440920).

Almost surely, 2^81944197485 is an apocalyptic number.

It is an amenable number.

81944197485 is a deficient number, since it is larger than the sum of its proper divisors (55125911955).

81944197485 is an equidigital number, since it uses as much as digits as its factorization.

81944197485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449074 (or 449028 counting only the distinct ones).

The product of its digits is 11612160, while the sum is 60.

The spelling of 81944197485 in words is "eighty-one billion, nine hundred forty-four million, one hundred ninety-seven thousand, four hundred eighty-five".