215650861 has 2 divisors, whose sum is σ = 215650862. Its totient is φ = 215650860.

The previous prime is 215650859. The next prime is 215650879. The reversal of 215650861 is 168056512.

It is a happy number.

215650861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204661636 + 10989225 = 14306^2 + 3315^2 .

It is a cyclic number.

It is not a de Polignac number, because 215650861 - 2¹ = 215650859 is a prime.

Together with 215650859, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215653861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107825430 + 107825431.

It is an arithmetic number, because the mean of its divisors is an integer number (107825431).

Almost surely, 2^215650861 is an apocalyptic number.

It is an amenable number.

215650861 is a deficient number, since it is larger than the sum of its proper divisors (1).

215650861 is an equidigital number, since it uses as much as digits as its factorization.

215650861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 215650861 is about 14685.0557029928. The cubic root of 215650861 is about 599.6765488117.

The spelling of 215650861 in words is "two hundred fifteen million, six hundred fifty thousand, eight hundred sixty-one".