19611961 has 16 divisors (see below), whose sum is σ = 20955024. Its totient is φ = 18330624.

The previous prime is 19611953. The next prime is 19611973. The reversal of 19611961 is 16911691.

It can be written as a sum of positive squares in 8 ways, for example, as 3258025 + 16353936 = 1805^2 + 4044^2 .

It is a cyclic number.

It is not a de Polignac number, because 19611961 - 2³ = 19611953 is a prime.

19611961 is a strobogrammatic number because it is the same when read upside-down.

It is not an unprimeable number, because it can be changed into a prime (19611901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 143085 + ... + 143221.

It is an arithmetic number, because the mean of its divisors is an integer number (1309689).

Almost surely, 2^19611961 is an apocalyptic number.

It is an amenable number.

19611961 is a deficient number, since it is larger than the sum of its proper divisors (1343063).

19611961 is a wasteful number, since it uses less digits than its factorization.

19611961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300.

The product of its digits is 2916, while the sum is 34.

The square root of 19611961 is about 4428.5393754600. The cubic root of 19611961 is about 269.6747844748.

The spelling of 19611961 in words is "nineteen million, six hundred eleven thousand, nine hundred sixty-one".