161556690401 has 8 divisors (see below), whose sum is σ = 161743727208. Its totient is φ = 161369712000.

The previous prime is 161556690311. The next prime is 161556690409. The reversal of 161556690401 is 104096655161.

It can be written as a sum of positive squares in 4 ways, for example, as 32477446225 + 129079244176 = 180215^2 + 359276^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161556690401 - 2¹⁰ = 161556689377 is a prime.

It is a super-2 number, since 2×161556690401² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161556690409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7893341 + ... + 7913781.

It is an arithmetic number, because the mean of its divisors is an integer number (20217965901).

Almost surely, 2^161556690401 is an apocalyptic number.

It is an amenable number.

161556690401 is a deficient number, since it is larger than the sum of its proper divisors (187036807).

161556690401 is a wasteful number, since it uses less digits than its factorization.

161556690401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29203.

The product of its (nonzero) digits is 194400, while the sum is 44.

The spelling of 161556690401 in words is "one hundred sixty-one billion, five hundred fifty-six million, six hundred ninety thousand, four hundred one".