81647242431 has 32 divisors (see below), whose sum is σ = 110996324352. Its totient is φ = 53373959520.

The previous prime is 81647242429. The next prime is 81647242433. The reversal of 81647242431 is 13424274618.

It is an interprime number because it is at equal distance from previous prime (81647242429) and next prime (81647242433).

It is not a de Polignac number, because 81647242431 - 2¹ = 81647242429 is a prime.

It is a super-2 number, since 2×81647242431² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81647242433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 44786386 + ... + 44788208.

It is an arithmetic number, because the mean of its divisors is an integer number (3468635136).

Almost surely, 2^81647242431 is an apocalyptic number.

81647242431 is a deficient number, since it is larger than the sum of its proper divisors (29349081921).

81647242431 is a wasteful number, since it uses less digits than its factorization.

81647242431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2923.

The product of its digits is 258048, while the sum is 42.

The spelling of 81647242431 in words is "eighty-one billion, six hundred forty-seven million, two hundred forty-two thousand, four hundred thirty-one".