81940855909 has 8 divisors (see below), whose sum is σ = 89534910528. Its totient is φ = 74370948960.

The previous prime is 81940855897. The next prime is 81940855937. The reversal of 81940855909 is 90955804918.

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

It is not a de Polignac number, because 81940855909 - 2¹⁷ = 81940724837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81940855939) 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, 6029817 + ... + 6043390.

It is an arithmetic number, because the mean of its divisors is an integer number (11191863816).

Almost surely, 2^81940855909 is an apocalyptic number.

It is an amenable number.

81940855909 is a deficient number, since it is larger than the sum of its proper divisors (7594054619).

81940855909 is a wasteful number, since it uses less digits than its factorization.

81940855909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12073835.

The product of its (nonzero) digits is 4665600, while the sum is 58.

The spelling of 81940855909 in words is "eighty-one billion, nine hundred forty million, eight hundred fifty-five thousand, nine hundred nine".