215013661 has 2 divisors, whose sum is σ = 215013662. Its totient is φ = 215013660.

The previous prime is 215013649. The next prime is 215013677. The reversal of 215013661 is 166310512.

215013661 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., 201100761 + 13912900 = 14181^2 + 3730^2 .

It is a cyclic number.

It is not a de Polignac number, because 215013661 - 2⁵ = 215013629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215013761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107506830 + 107506831.

It is an arithmetic number, because the mean of its divisors is an integer number (107506831).

Almost surely, 2^215013661 is an apocalyptic number.

It is an amenable number.

215013661 is a deficient number, since it is larger than the sum of its proper divisors (1).

215013661 is an equidigital number, since it uses as much as digits as its factorization.

215013661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 215013661 is about 14663.3441274492. The cubic root of 215013661 is about 599.0853294865.

The spelling of 215013661 in words is "two hundred fifteen million, thirteen thousand, six hundred sixty-one".