81637405343 has 4 divisors (see below), whose sum is σ = 87917205768. Its totient is φ = 75357604920.

The previous prime is 81637405327. The next prime is 81637405363. The reversal of 81637405343 is 34350473618.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 81637405343 - 2⁴ = 81637405327 is a prime.

It is a super-2 number, since 2×81637405343² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81637405294 and 81637405303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81637405363) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3139900193 + ... + 3139900218.

It is an arithmetic number, because the mean of its divisors is an integer number (21979301442).

Almost surely, 2^81637405343 is an apocalyptic number.

81637405343 is a deficient number, since it is larger than the sum of its proper divisors (6279800425).

81637405343 is a wasteful number, since it uses less digits than its factorization.

81637405343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6279800424.

The product of its (nonzero) digits is 725760, while the sum is 44.

The spelling of 81637405343 in words is "eighty-one billion, six hundred thirty-seven million, four hundred five thousand, three hundred forty-three".