2166709421 has 2 divisors, whose sum is σ = 2166709422. Its totient is φ = 2166709420.

The previous prime is 2166709399. The next prime is 2166709427. The reversal of 2166709421 is 1249076612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2090775625 + 75933796 = 45725^2 + 8714^2 .

It is a cyclic number.

It is not a de Polignac number, because 2166709421 - 2⁶ = 2166709357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2166709427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1083354710 + 1083354711.

It is an arithmetic number, because the mean of its divisors is an integer number (1083354711).

Almost surely, 2^2166709421 is an apocalyptic number.

It is an amenable number.

2166709421 is a deficient number, since it is larger than the sum of its proper divisors (1).

2166709421 is an equidigital number, since it uses as much as digits as its factorization.

2166709421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 2166709421 is about 46547.9260655080. The cubic root of 2166709421 is about 1293.9978573845.

The spelling of 2166709421 in words is "two billion, one hundred sixty-six million, seven hundred nine thousand, four hundred twenty-one".