1209816 has 40 divisors (see below), whose sum is σ = 3390420. Its totient is φ = 403056.

The previous prime is 1209811. The next prime is 1209821. The reversal of 1209816 is 6189021.

It is an interprime number because it is at equal distance from previous prime (1209811) and next prime (1209821).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 1209816.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1209811) 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 9 ways as a sum of consecutive naturals, for example, 286 + ... + 1581.

2^1209816 is an apocalyptic number.

It is an amenable number.

1209816 is an abundant number, since it is smaller than the sum of its proper divisors (2180604).

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

1209816 is a wasteful number, since it uses less digits than its factorization.

1209816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1885 (or 1872 counting only the distinct ones).

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

The square root of 1209816 is about 1099.9163604566. The cubic root of 1209816 is about 106.5548220031.

It can be divided in two parts, 1209 and 816, that added together give a square (2025 = 45²).

The spelling of 1209816 in words is "one million, two hundred nine thousand, eight hundred sixteen".