861921917239 has 2 divisors, whose sum is σ = 861921917240. Its totient is φ = 861921917238.

The previous prime is 861921917221. The next prime is 861921917251. The reversal of 861921917239 is 932719129168.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 861921917239 - 2²⁷ = 861787699511 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861921017239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430960958619 + 430960958620.

It is an arithmetic number, because the mean of its divisors is an integer number (430960958620).

Almost surely, 2^861921917239 is an apocalyptic number.

861921917239 is a deficient number, since it is larger than the sum of its proper divisors (1).

861921917239 is an equidigital number, since it uses as much as digits as its factorization.

861921917239 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2939328, while the sum is 58.

The spelling of 861921917239 in words is "eight hundred sixty-one billion, nine hundred twenty-one million, nine hundred seventeen thousand, two hundred thirty-nine".