81620537182739 has 2 divisors, whose sum is σ = 81620537182740. Its totient is φ = 81620537182738.

The previous prime is 81620537182693. The next prime is 81620537182819. The reversal of 81620537182739 is 93728173502618.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81620537182739 is a prime.

It is not a weakly prime, because it can be changed into another prime (81620537182139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40810268591369 + 40810268591370.

It is an arithmetic number, because the mean of its divisors is an integer number (40810268591370).

Almost surely, 2^{81620537182739} is an apocalyptic number.

81620537182739 is a deficient number, since it is larger than the sum of its proper divisors (1).

81620537182739 is an equidigital number, since it uses as much as digits as its factorization.

81620537182739 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30481920, while the sum is 62.

The spelling of 81620537182739 in words is "eighty-one trillion, six hundred twenty billion, five hundred thirty-seven million, one hundred eighty-two thousand, seven hundred thirty-nine".