161686767621790 has 32 divisors (see below), whose sum is σ = 293863719554496. Its totient is φ = 64046373615360.

The previous prime is 161686767621767. The next prime is 161686767621889. The reversal of 161686767621790 is 97126767686161.

It is a super-2 number, since 2×161686767621790² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 188743474 + ... + 189598186.

It is an arithmetic number, because the mean of its divisors is an integer number (9183241236078).

Almost surely, 2^{161686767621790} is an apocalyptic number.

161686767621790 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161686767621790 is a deficient number, since it is larger than the sum of its proper divisors (132176951932706).

161686767621790 is a wasteful number, since it uses less digits than its factorization.

161686767621790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1038484.

The product of its (nonzero) digits is 384072192, while the sum is 73.

The spelling of 161686767621790 in words is "one hundred sixty-one trillion, six hundred eighty-six billion, seven hundred sixty-seven million, six hundred twenty-one thousand, seven hundred ninety".