1213831 has 4 divisors (see below), whose sum is σ = 1216152. Its totient is φ = 1211512.

The previous prime is 1213829. The next prime is 1213837. The reversal of 1213831 is 1383121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1213831 - 2¹ = 1213829 is a prime.

It is a super-2 number, since 2×1213831² = 2946771393122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213799 and 1213808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213837) 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, 36 + ... + 1558.

It is an arithmetic number, because the mean of its divisors is an integer number (304038).

2^1213831 is an apocalyptic number.

1213831 is a deficient number, since it is larger than the sum of its proper divisors (2321).

1213831 is an equidigital number, since it uses as much as digits as its factorization.

1213831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2320.

The product of its digits is 144, while the sum is 19.

The square root of 1213831 is about 1101.7399874744. The cubic root of 1213831 is about 106.6725658630.

Adding to 1213831 its reverse (1383121), we get a palindrome (2596952).

It can be divided in two parts, 12138 and 31, that multiplied together give a triangular number (376278 = T₈₆₇).

The spelling of 1213831 in words is "one million, two hundred thirteen thousand, eight hundred thirty-one".