81185901350431 has 2 divisors, whose sum is σ = 81185901350432. Its totient is φ = 81185901350430.

The previous prime is 81185901350399. The next prime is 81185901350581. The reversal of 81185901350431 is 13405310958118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81185901350431 - 2⁵ = 81185901350399 is a prime.

It is a super-2 number, since 2×81185901350431² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81185901350831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40592950675215 + 40592950675216.

It is an arithmetic number, because the mean of its divisors is an integer number (40592950675216).

Almost surely, 2^{81185901350431} is an apocalyptic number.

81185901350431 is a deficient number, since it is larger than the sum of its proper divisors (1).

81185901350431 is an equidigital number, since it uses as much as digits as its factorization.

81185901350431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 518400, while the sum is 49.

The spelling of 81185901350431 in words is "eighty-one trillion, one hundred eighty-five billion, nine hundred one million, three hundred fifty thousand, four hundred thirty-one".