8161291993680 has 560 divisors, whose sum is σ = 32612473156224. Its totient is φ = 1859771612160.

The previous prime is 8161291993667. The next prime is 8161291993691. The reversal of 8161291993680 is 863991921618.

8161291993680 is a `hidden beast` number, since 8 + 1 + 61 + 29 + 199 + 368 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (560).

It is a super-2 number, since 2×8161291993680² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 135097242 + ... + 135157638.

Almost surely, 2^{8161291993680} is an apocalyptic number.

8161291993680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8161291993680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16306236578112).

8161291993680 is an abundant number, since it is smaller than the sum of its proper divisors (24451181162544).

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

8161291993680 is a wasteful number, since it uses less digits than its factorization.

8161291993680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60766 (or 60745 counting only the distinct ones).

The product of its (nonzero) digits is 10077696, while the sum is 63.

The spelling of 8161291993680 in words is "eight trillion, one hundred sixty-one billion, two hundred ninety-one million, nine hundred ninety-three thousand, six hundred eighty".