161563021261 has 16 divisors (see below), whose sum is σ = 171372516480. Its totient is φ = 151787750400.

The previous prime is 161563021231. The next prime is 161563021273. The reversal of 161563021261 is 162120365161.

It is not a de Polignac number, because 161563021261 - 2¹⁹ = 161562496973 is a prime.

It is a super-2 number, since 2×161563021261² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161563021231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37250085 + ... + 37254421.

It is an arithmetic number, because the mean of its divisors is an integer number (10710782280).

Almost surely, 2^161563021261 is an apocalyptic number.

It is an amenable number.

161563021261 is a deficient number, since it is larger than the sum of its proper divisors (9809495219).

161563021261 is a wasteful number, since it uses less digits than its factorization.

161563021261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7764.

The product of its (nonzero) digits is 12960, while the sum is 34.

The spelling of 161563021261 in words is "one hundred sixty-one billion, five hundred sixty-three million, twenty-one thousand, two hundred sixty-one".