161661511055 has 8 divisors (see below), whose sum is σ = 211629614544. Its totient is φ = 117572008000.

The previous prime is 161661510971. The next prime is 161661511079. The reversal of 161661511055 is 550115166161.

It is a happy number.

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

It is not a de Polignac number, because 161661511055 - 2¹² = 161661506959 is a prime.

It is a super-2 number, since 2×161661511055² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1469650046 + ... + 1469650155.

It is an arithmetic number, because the mean of its divisors is an integer number (26453701818).

Almost surely, 2^161661511055 is an apocalyptic number.

161661511055 is a deficient number, since it is larger than the sum of its proper divisors (49968103489).

161661511055 is a wasteful number, since it uses less digits than its factorization.

161661511055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2939300217.

The product of its (nonzero) digits is 27000, while the sum is 38.

The spelling of 161661511055 in words is "one hundred sixty-one billion, six hundred sixty-one million, five hundred eleven thousand, fifty-five".