215638939 has 6 divisors (see below), whose sum is σ = 217805420. Its totient is φ = 213493800.

The previous prime is 215638921. The next prime is 215638957. The reversal of 215638939 is 939836512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (215638921) and next prime (215638957).

It is not a de Polignac number, because 215638939 - 2⁷ = 215638811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215638979) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 369 + ... + 20770.

Almost surely, 2^215638939 is an apocalyptic number.

215638939 is a deficient number, since it is larger than the sum of its proper divisors (2166481).

215638939 is an equidigital number, since it uses as much as digits as its factorization.

215638939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21341 (or 21240 counting only the distinct ones).

The product of its digits is 349920, while the sum is 46.

The square root of 215638939 is about 14684.6497745094. The cubic root of 215638939 is about 599.6654978077.

The spelling of 215638939 in words is "two hundred fifteen million, six hundred thirty-eight thousand, nine hundred thirty-nine".