861215939 has 2 divisors, whose sum is σ = 861215940. Its totient is φ = 861215938.

The previous prime is 861215917. The next prime is 861215941. The reversal of 861215939 is 939512168.

It is a happy number.

861215939 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861215939 is a prime.

Together with 861215941, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 861215939.

It is not a weakly prime, because it can be changed into another prime (861215039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430607969 + 430607970.

It is an arithmetic number, because the mean of its divisors is an integer number (430607970).

Almost surely, 2^861215939 is an apocalyptic number.

861215939 is a deficient number, since it is larger than the sum of its proper divisors (1).

861215939 is an equidigital number, since it uses as much as digits as its factorization.

861215939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 44.

The square root of 861215939 is about 29346.4808622772. The cubic root of 861215939 is about 951.4165161888.

The spelling of 861215939 in words is "eight hundred sixty-one million, two hundred fifteen thousand, nine hundred thirty-nine".