161944874864640 has 3328 divisors, whose sum is σ = 720339134054400. Its totient is φ = 33681899520000.

The previous prime is 161944874864629. The next prime is 161944874864681. The reversal of 161944874864640 is 46468478449161.

161944874864640 is a `hidden beast` number, since 1 + 6 + 1 + 9 + 4 + 4 + 87 + 4 + 86 + 464 + 0 = 666.

It is a super-2 number, since 2×161944874864640² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 572243373939 + ... + 572243374221.

Almost surely, 2^{161944874864640} is an apocalyptic number.

161944874864640 is a gapful number since it is divisible by the number (10) 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 161944874864640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (360169567027200).

161944874864640 is an abundant number, since it is smaller than the sum of its proper divisors (558394259189760).

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

161944874864640 is a wasteful number, since it uses less digits than its factorization.

161944874864640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 629 (or 601 counting only the distinct ones).

The product of its (nonzero) digits is 891813888, while the sum is 72.

The spelling of 161944874864640 in words is "one hundred sixty-one trillion, nine hundred forty-four billion, eight hundred seventy-four million, eight hundred sixty-four thousand, six hundred forty".