81919276973 has 2 divisors, whose sum is σ = 81919276974. Its totient is φ = 81919276972.

The previous prime is 81919276931. The next prime is 81919276993. The reversal of 81919276973 is 37967291918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42595593769 + 39323683204 = 206387^2 + 198302^2 .

It is a cyclic number.

It is not a de Polignac number, because 81919276973 - 2¹⁸ = 81919014829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81919276903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40959638486 + 40959638487.

It is an arithmetic number, because the mean of its divisors is an integer number (40959638487).

Almost surely, 2^81919276973 is an apocalyptic number.

It is an amenable number.

81919276973 is a deficient number, since it is larger than the sum of its proper divisors (1).

81919276973 is an equidigital number, since it uses as much as digits as its factorization.

81919276973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10287648, while the sum is 62.

The spelling of 81919276973 in words is "eighty-one billion, nine hundred nineteen million, two hundred seventy-six thousand, nine hundred seventy-three".