81961367376 has 160 divisors (see below), whose sum is σ = 256060182528. Its totient is φ = 22083747840.

The previous prime is 81961367357. The next prime is 81961367413. The reversal of 81961367376 is 67376316918.

It is a congruent number.

It is an unprimeable number.

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, 474000 + ... + 623376.

Almost surely, 2^81961367376 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81961367376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128030091264).

81961367376 is an abundant number, since it is smaller than the sum of its proper divisors (174098815152).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81961367376 is a wasteful number, since it uses less digits than its factorization.

81961367376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149489 (or 149483 counting only the distinct ones).

The product of its digits is 6858432, while the sum is 57.

The spelling of 81961367376 in words is "eighty-one billion, nine hundred sixty-one million, three hundred sixty-seven thousand, three hundred seventy-six".