1231856869 has 4 divisors (see below), whose sum is σ = 1232563744. Its totient is φ = 1231149996.

The previous prime is 1231856861. The next prime is 1231856891. The reversal of 1231856869 is 9686581321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1231856869 - 2³ = 1231856861 is a prime.

It is a super-2 number, since 2×1231856869² = 3034942691404966322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231856861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 350817 + ... + 354310.

It is an arithmetic number, because the mean of its divisors is an integer number (308140936).

Almost surely, 2^1231856869 is an apocalyptic number.

It is an amenable number.

1231856869 is a deficient number, since it is larger than the sum of its proper divisors (706875).

1231856869 is an equidigital number, since it uses as much as digits as its factorization.

1231856869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 706874.

The product of its digits is 622080, while the sum is 49.

The square root of 1231856869 is about 35097.8185789374. The cubic root of 1231856869 is about 1071.9801655595.

The spelling of 1231856869 in words is "one billion, two hundred thirty-one million, eight hundred fifty-six thousand, eight hundred sixty-nine".