181213716491 has 2 divisors, whose sum is σ = 181213716492. Its totient is φ = 181213716490.

The previous prime is 181213716479. The next prime is 181213716623. The reversal of 181213716491 is 194617312181.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 181213716491 - 2¹⁸ = 181213454347 is a prime.

It is a super-2 number, since 2×181213716491² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (181213716461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90606858245 + 90606858246.

It is an arithmetic number, because the mean of its divisors is an integer number (90606858246).

Almost surely, 2^181213716491 is an apocalyptic number.

181213716491 is a deficient number, since it is larger than the sum of its proper divisors (1).

181213716491 is an equidigital number, since it uses as much as digits as its factorization.

181213716491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 44.

The spelling of 181213716491 in words is "one hundred eighty-one billion, two hundred thirteen million, seven hundred sixteen thousand, four hundred ninety-one".