861505499 has 2 divisors, whose sum is σ = 861505500. Its totient is φ = 861505498.

The previous prime is 861505439. The next prime is 861505529. The reversal of 861505499 is 994505168.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 861505499 - 2²⁰ = 860456923 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (861505439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430752749 + 430752750.

It is an arithmetic number, because the mean of its divisors is an integer number (430752750).

Almost surely, 2^861505499 is an apocalyptic number.

861505499 is a deficient number, since it is larger than the sum of its proper divisors (1).

861505499 is an equidigital number, since it uses as much as digits as its factorization.

861505499 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 388800, while the sum is 47.

The square root of 861505499 is about 29351.4139182425. The cubic root of 861505499 is about 951.5231333890.

The spelling of 861505499 in words is "eight hundred sixty-one million, five hundred five thousand, four hundred ninety-nine".