16391961 has 12 divisors (see below), whose sum is σ = 25070292. Its totient is φ = 10285056.

The previous prime is 16391941. The next prime is 16391971. The reversal of 16391961 is 16919361.

16391961 is a `hidden beast` number, since 1 + 639 + 19 + 6 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13395600 + 2996361 = 3660^2 + 1731^2 .

It is not a de Polignac number, because 16391961 - 2⁵ = 16391929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16391941) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53416 + ... + 53721.

It is an arithmetic number, because the mean of its divisors is an integer number (2089191).

Almost surely, 2^16391961 is an apocalyptic number.

It is an amenable number.

16391961 is a deficient number, since it is larger than the sum of its proper divisors (8678331).

16391961 is a wasteful number, since it uses less digits than its factorization.

16391961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107160 (or 107157 counting only the distinct ones).

The product of its digits is 8748, while the sum is 36.

The square root of 16391961 is about 4048.6986798229. The cubic root of 16391961 is about 254.0252986974.

It can be divided in two parts, 1639 and 1961, that added together give a square (3600 = 60²).

The spelling of 16391961 in words is "sixteen million, three hundred ninety-one thousand, nine hundred sixty-one".