161709337681920 has 784 divisors, whose sum is σ = 664974473065920. Its totient is φ = 36962086551552.

The previous prime is 161709337681919. The next prime is 161709337681933. The reversal of 161709337681920 is 29186733907161.

161709337681920 is a `hidden beast` number, since 1 + 6 + 1 + 70 + 9 + 3 + 376 + 8 + 192 + 0 = 666.

It is a super-2 number, since 2×161709337681920² (a number of 29 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 208632051 + ... + 209405709.

Almost surely, 2^{161709337681920} is an apocalyptic number.

161709337681920 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 161709337681920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (332487236532960).

161709337681920 is an abundant number, since it is smaller than the sum of its proper divisors (503265135384000).

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

161709337681920 is an frugal number, since it uses more digits than its factorization.

161709337681920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 773715 (or 773676 counting only the distinct ones).

The product of its (nonzero) digits is 20575296, while the sum is 63.

The spelling of 161709337681920 in words is "one hundred sixty-one trillion, seven hundred nine billion, three hundred thirty-seven million, six hundred eighty-one thousand, nine hundred twenty".