1215631 has 2 divisors, whose sum is σ = 1215632. Its totient is φ = 1215630.

The previous prime is 1215629. The next prime is 1215637. The reversal of 1215631 is 1365121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1215631 - 2¹ = 1215629 is a prime.

It is a super-2 number, since 2×1215631² = 2955517456322, which contains 22 as substring.

Together with 1215629, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1215599 and 1215608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607815 + 607816.

It is an arithmetic number, because the mean of its divisors is an integer number (607816).

2^1215631 is an apocalyptic number.

1215631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215631 is an equidigital number, since it uses as much as digits as its factorization.

1215631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 180, while the sum is 19.

The square root of 1215631 is about 1102.5565745122. The cubic root of 1215631 is about 106.7252683631.

The spelling of 1215631 in words is "one million, two hundred fifteen thousand, six hundred thirty-one".