1218731 has 2 divisors, whose sum is σ = 1218732. Its totient is φ = 1218730.

The previous prime is 1218727. The next prime is 1218739. The reversal of 1218731 is 1378121.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1218731 - 2² = 1218727 is a prime.

It is a super-2 number, since 2×1218731² = 2970610500722, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1218697 and 1218706.

It is not a weakly prime, because it can be changed into another prime (1218739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609365 + 609366.

It is an arithmetic number, because the mean of its divisors is an integer number (609366).

2^1218731 is an apocalyptic number.

1218731 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218731 is an equidigital number, since it uses as much as digits as its factorization.

1218731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336, while the sum is 23.

The square root of 1218731 is about 1103.9615029520. The cubic root of 1218731 is about 106.8159119591.

The spelling of 1218731 in words is "one million, two hundred eighteen thousand, seven hundred thirty-one".