2166642397 has 2 divisors, whose sum is σ = 2166642398. Its totient is φ = 2166642396.

The previous prime is 2166642383. The next prime is 2166642431. The reversal of 2166642397 is 7932466612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2165878521 + 763876 = 46539^2 + 874^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2166642397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2166642497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1083321198 + 1083321199.

It is an arithmetic number, because the mean of its divisors is an integer number (1083321199).

Almost surely, 2^2166642397 is an apocalyptic number.

It is an amenable number.

2166642397 is a deficient number, since it is larger than the sum of its proper divisors (1).

2166642397 is an equidigital number, since it uses as much as digits as its factorization.

2166642397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 46.

The square root of 2166642397 is about 46547.2061137938. The cubic root of 2166642397 is about 1293.9845146006.

The spelling of 2166642397 in words is "two billion, one hundred sixty-six million, six hundred forty-two thousand, three hundred ninety-seven".