81083978889 has 12 divisors (see below), whose sum is σ = 114845590704. Its totient is φ = 50876221504.

The previous prime is 81083978881. The next prime is 81083978897. The reversal of 81083978889 is 98887938018.

It is an interprime number because it is at equal distance from previous prime (81083978881) and next prime (81083978897).

It is not a de Polignac number, because 81083978889 - 2³ = 81083978881 is a prime.

It is a super-2 number, since 2×81083978889² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81083978881) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 46760367 + ... + 46762100.

It is an arithmetic number, because the mean of its divisors is an integer number (9570465892).

Almost surely, 2^81083978889 is an apocalyptic number.

It is an amenable number.

81083978889 is a deficient number, since it is larger than the sum of its proper divisors (33761611815).

81083978889 is a wasteful number, since it uses less digits than its factorization.

81083978889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93522504 (or 93522487 counting only the distinct ones).

The product of its (nonzero) digits is 55738368, while the sum is 69.

The spelling of 81083978889 in words is "eighty-one billion, eighty-three million, nine hundred seventy-eight thousand, eight hundred eighty-nine".