81082637989 has 2 divisors, whose sum is σ = 81082637990. Its totient is φ = 81082637988.

The previous prime is 81082637981. The next prime is 81082638089. The reversal of 81082637989 is 98973628018.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57017321089 + 24065316900 = 238783^2 + 155130^2 .

It is a cyclic number.

It is not a de Polignac number, because 81082637989 - 2³ = 81082637981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81082637981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40541318994 + 40541318995.

It is an arithmetic number, because the mean of its divisors is an integer number (40541318995).

Almost surely, 2^81082637989 is an apocalyptic number.

It is an amenable number.

81082637989 is a deficient number, since it is larger than the sum of its proper divisors (1).

81082637989 is an equidigital number, since it uses as much as digits as its factorization.

81082637989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10450944, while the sum is 61.

The spelling of 81082637989 in words is "eighty-one billion, eighty-two million, six hundred thirty-seven thousand, nine hundred eighty-nine".