81947377329 has 8 divisors (see below), whose sum is σ = 109515511392. Its totient is φ = 54505414080.

The previous prime is 81947377319. The next prime is 81947377339. The reversal of 81947377329 is 92377374918.

It is an interprime number because it is at equal distance from previous prime (81947377319) and next prime (81947377339).

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

It is not a de Polignac number, because 81947377329 - 2¹⁶ = 81947311793 is a prime.

It is a super-2 number, since 2×81947377329² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81947377319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31541187 + ... + 31543784.

It is an arithmetic number, because the mean of its divisors is an integer number (13689438924).

Almost surely, 2^81947377329 is an apocalyptic number.

It is an amenable number.

81947377329 is a deficient number, since it is larger than the sum of its proper divisors (27568134063).

81947377329 is a wasteful number, since it uses less digits than its factorization.

81947377329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63085407.

The product of its digits is 16003008, while the sum is 60.

The spelling of 81947377329 in words is "eighty-one billion, nine hundred forty-seven million, three hundred seventy-seven thousand, three hundred twenty-nine".