161913961 has 32 divisors (see below), whose sum is σ = 192439296. Its totient is φ = 134784000.

The previous prime is 161913937. The next prime is 161913977. The reversal of 161913961 is 169319161.

161913961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a 4-Lehmer number, since φ(161913961) divides (161913961-1)⁴.

It is a cyclic number.

It is a Carmichael number.

It is not a de Polignac number, because 161913961 - 2¹¹ = 161911913 is a prime.

It is a super-2 number, since 2×161913961² = 52432261533419042, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a deceptive number, since it divides R_161913960.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161913961.

It is not an unprimeable number, because it can be changed into a prime (161913911) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 517141 + ... + 517453.

It is an arithmetic number, because the mean of its divisors is an integer number (6013728).

It is a Poulet number, since it divides 2^161913960-1.

Almost surely, 2^161913961 is an apocalyptic number.

161913961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

161913961 is a deficient number, since it is larger than the sum of its proper divisors (30525335).

161913961 is a wasteful number, since it uses less digits than its factorization.

161913961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433.

The product of its digits is 8748, while the sum is 37.

The square root of 161913961 is about 12724.5416813338. The cubic root of 161913961 is about 545.0396525872.

The spelling of 161913961 in words is "one hundred sixty-one million, nine hundred thirteen thousand, nine hundred sixty-one".