81353614381 has 4 divisors (see below), whose sum is σ = 87611584732. Its totient is φ = 75095644032.

The previous prime is 81353614361. The next prime is 81353614457. The reversal of 81353614381 is 18341635318.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10219390281 + 71134224100 = 101091^2 + 266710^2 .

It is a cyclic number.

It is not a de Polignac number, because 81353614381 - 2⁷ = 81353614253 is a prime.

It is a super-2 number, since 2×81353614381² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81353614361) 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 3 ways as a sum of consecutive naturals, for example, 3128985156 + ... + 3128985181.

It is an arithmetic number, because the mean of its divisors is an integer number (21902896183).

Almost surely, 2^81353614381 is an apocalyptic number.

It is an amenable number.

81353614381 is a deficient number, since it is larger than the sum of its proper divisors (6257970351).

81353614381 is a wasteful number, since it uses less digits than its factorization.

81353614381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6257970350.

The product of its digits is 207360, while the sum is 43.

The spelling of 81353614381 in words is "eighty-one billion, three hundred fifty-three million, six hundred fourteen thousand, three hundred eighty-one".