81121871983 has 2 divisors, whose sum is σ = 81121871984. Its totient is φ = 81121871982.

The previous prime is 81121871947. The next prime is 81121871993. The reversal of 81121871983 is 38917812118.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81121871983 is a prime.

It is a super-2 number, since 2×81121871983² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81121871993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40560935991 + 40560935992.

It is an arithmetic number, because the mean of its divisors is an integer number (40560935992).

Almost surely, 2^81121871983 is an apocalyptic number.

81121871983 is a deficient number, since it is larger than the sum of its proper divisors (1).

81121871983 is an equidigital number, since it uses as much as digits as its factorization.

81121871983 is an evil number, because the sum of its binary digits is even.

The product of its digits is 193536, while the sum is 49.

The spelling of 81121871983 in words is "eighty-one billion, one hundred twenty-one million, eight hundred seventy-one thousand, nine hundred eighty-three".