191664061 has 2 divisors, whose sum is σ = 191664062. Its totient is φ = 191664060.

The previous prime is 191664049. The next prime is 191664079. The reversal of 191664061 is 160466191.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 187279225 + 4384836 = 13685^2 + 2094^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191664061 is a prime.

It is a super-2 number, since 2×191664061² = 73470224558023442, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194664061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95832030 + 95832031.

It is an arithmetic number, because the mean of its divisors is an integer number (95832031).

Almost surely, 2^191664061 is an apocalyptic number.

It is an amenable number.

191664061 is a deficient number, since it is larger than the sum of its proper divisors (1).

191664061 is an equidigital number, since it uses as much as digits as its factorization.

191664061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 191664061 is about 13844.2789989223. The cubic root of 191664061 is about 576.5631678926.

The spelling of 191664061 in words is "one hundred ninety-one million, six hundred sixty-four thousand, sixty-one".