861669869 has 2 divisors, whose sum is σ = 861669870. Its totient is φ = 861669868.

The previous prime is 861669859. The next prime is 861669943. The reversal of 861669869 is 968966168.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 703840900 + 157828969 = 26530^2 + 12563^2 .

It is a cyclic number.

It is not a de Polignac number, because 861669869 - 2¹² = 861665773 is a prime.

It is a super-2 number, since 2×861669869² = 1484949926284954322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861669859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430834934 + 430834935.

It is an arithmetic number, because the mean of its divisors is an integer number (430834935).

Almost surely, 2^861669869 is an apocalyptic number.

It is an amenable number.

861669869 is a deficient number, since it is larger than the sum of its proper divisors (1).

861669869 is an equidigital number, since it uses as much as digits as its factorization.

861669869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6718464, while the sum is 59.

The square root of 861669869 is about 29354.2138201656. The cubic root of 861669869 is about 951.5836444795.

The spelling of 861669869 in words is "eight hundred sixty-one million, six hundred sixty-nine thousand, eight hundred sixty-nine".