1218690 has 48 divisors (see below), whose sum is σ = 3459456. Its totient is φ = 295200.

The previous prime is 1218683. The next prime is 1218691. The reversal of 1218690 is 968121.

It is a super-2 number, since 2×1218690² = 2970410632200, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1218691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 375 + ... + 1605.

It is an arithmetic number, because the mean of its divisors is an integer number (72072).

2^1218690 is an apocalyptic number.

1218690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1218690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1729728).

1218690 is an abundant number, since it is smaller than the sum of its proper divisors (2240766).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1218690 is a wasteful number, since it uses less digits than its factorization.

1218690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1255 (or 1252 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 1218690 is about 1103.9429333077. The cubic root of 1218690 is about 106.8147141281.

The spelling of 1218690 in words is "one million, two hundred eighteen thousand, six hundred ninety".