869919781 has 2 divisors, whose sum is σ = 869919782. Its totient is φ = 869919780.

The previous prime is 869919749. The next prime is 869919803. The reversal of 869919781 is 187919968.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 438693025 + 431226756 = 20945^2 + 20766^2 .

It is a cyclic number.

It is not a de Polignac number, because 869919781 - 2⁵ = 869919749 is a prime.

It is a super-2 number, since 2×869919781² = 1513520850750175922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (869914781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 434959890 + 434959891.

It is an arithmetic number, because the mean of its divisors is an integer number (434959891).

Almost surely, 2^869919781 is an apocalyptic number.

It is an amenable number.

869919781 is a deficient number, since it is larger than the sum of its proper divisors (1).

869919781 is an equidigital number, since it uses as much as digits as its factorization.

869919781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1959552, while the sum is 58.

The square root of 869919781 is about 29494.4025367526. The cubic root of 869919781 is about 954.6109289277.

The spelling of 869919781 in words is "eight hundred sixty-nine million, nine hundred nineteen thousand, seven hundred eighty-one".