81965437124 has 12 divisors (see below), whose sum is σ = 143441520684. Its totient is φ = 40982145504.

The previous prime is 81965437091. The next prime is 81965437187. The reversal of 81965437124 is 42173456918.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21465180100 + 60500257024 = 146510^2 + 245968^2 .

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, 475382 + ... + 624434.

It is an arithmetic number, because the mean of its divisors is an integer number (11953460057).

Almost surely, 2^81965437124 is an apocalyptic number.

It is an amenable number.

81965437124 is a deficient number, since it is larger than the sum of its proper divisors (61476083560).

81965437124 is a wasteful number, since it uses less digits than its factorization.

81965437124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286534 (or 286532 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 50.

The spelling of 81965437124 in words is "eighty-one billion, nine hundred sixty-five million, four hundred thirty-seven thousand, one hundred twenty-four".