81351649519 has 8 divisors (see below), whose sum is σ = 92992479008. Its totient is φ = 69715611360.

The previous prime is 81351649517. The next prime is 81351649523. The reversal of 81351649519 is 91594615318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81351649519 - 2¹ = 81351649517 is a prime.

It is a super-2 number, since 2×81351649519² (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 (81351649517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1161372 + ... + 1229425.

It is an arithmetic number, because the mean of its divisors is an integer number (11624059876).

Almost surely, 2^81351649519 is an apocalyptic number.

81351649519 is a deficient number, since it is larger than the sum of its proper divisors (11640829489).

81351649519 is a wasteful number, since it uses less digits than its factorization.

81351649519 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2395665.

The product of its digits is 1166400, while the sum is 52.

The spelling of 81351649519 in words is "eighty-one billion, three hundred fifty-one million, six hundred forty-nine thousand, five hundred nineteen".