1261831 has 2 divisors, whose sum is σ = 1261832. Its totient is φ = 1261830.

The previous prime is 1261829. The next prime is 1261837. The reversal of 1261831 is 1381621.

It is a weak prime.

It is an emirp because it is prime and its reverse (1381621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1261831 - 2¹ = 1261829 is a prime.

It is a super-2 number, since 2×1261831² = 3184434945122, which contains 22 as substring.

Together with 1261829, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1261837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630915 + 630916.

It is an arithmetic number, because the mean of its divisors is an integer number (630916).

2^1261831 is an apocalyptic number.

1261831 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261831 is an equidigital number, since it uses as much as digits as its factorization.

1261831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 22.

The square root of 1261831 is about 1123.3125121710. The cubic root of 1261831 is about 108.0605227756.

The spelling of 1261831 in words is "one million, two hundred sixty-one thousand, eight hundred thirty-one".