861121431 has 12 divisors (see below), whose sum is σ = 1258829208. Its totient is φ = 567163824.

The previous prime is 861121427. The next prime is 861121463. The reversal of 861121431 is 134121168.

It is a happy number.

861121431 is a `hidden beast` number, since 8 + 611 + 2 + 1 + 43 + 1 = 666.

It is not a de Polignac number, because 861121431 - 2² = 861121427 is a prime.

It is a super-2 number, since 2×861121431² = 1483060237854975522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 861121395 and 861121404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861121421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 575640 + ... + 577133.

It is an arithmetic number, because the mean of its divisors is an integer number (104902434).

Almost surely, 2^861121431 is an apocalyptic number.

861121431 is a deficient number, since it is larger than the sum of its proper divisors (397707777).

861121431 is a wasteful number, since it uses less digits than its factorization.

861121431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1152862 (or 1152859 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 861121431 is about 29344.8706079955. The cubic root of 861121431 is about 951.3817127760.

Adding to 861121431 its reverse (134121168), we get a palindrome (995242599).

The spelling of 861121431 in words is "eight hundred sixty-one million, one hundred twenty-one thousand, four hundred thirty-one".