215139387 has 4 divisors (see below), whose sum is σ = 286852520. Its totient is φ = 143426256.

The previous prime is 215139383. The next prime is 215139389. The reversal of 215139387 is 783931512.

215139387 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 215139387 - 2² = 215139383 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215139383) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35856562 + ... + 35856567.

It is an arithmetic number, because the mean of its divisors is an integer number (71713130).

Almost surely, 2^215139387 is an apocalyptic number.

215139387 is a deficient number, since it is larger than the sum of its proper divisors (71713133).

215139387 is an equidigital number, since it uses as much as digits as its factorization.

215139387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71713132.

The product of its digits is 45360, while the sum is 39.

The square root of 215139387 is about 14667.6305857490. The cubic root of 215139387 is about 599.2020754422.

The spelling of 215139387 in words is "two hundred fifteen million, one hundred thirty-nine thousand, three hundred eighty-seven".