1215831 has 4 divisors (see below), whose sum is σ = 1621112. Its totient is φ = 810552.

The previous prime is 1215827. The next prime is 1215839. The reversal of 1215831 is 1385121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1385121 = 3 ⋅461707.

It is not a de Polignac number, because 1215831 - 2² = 1215827 is a prime.

It is a super-2 number, since 2×1215831² = 2956490041122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1215798 and 1215807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1215839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202636 + ... + 202641.

It is an arithmetic number, because the mean of its divisors is an integer number (405278).

2^1215831 is an apocalyptic number.

1215831 is a deficient number, since it is larger than the sum of its proper divisors (405281).

1215831 is an equidigital number, since it uses as much as digits as its factorization.

1215831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405280.

The product of its digits is 240, while the sum is 21.

The square root of 1215831 is about 1102.6472690757. The cubic root of 1215831 is about 106.7311209843.

The spelling of 1215831 in words is "one million, two hundred fifteen thousand, eight hundred thirty-one".