1212821 has 4 divisors (see below), whose sum is σ = 1242444. Its totient is φ = 1183200.

The previous prime is 1212817. The next prime is 1212839. The reversal of 1212821 is 1282121.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 422500 + 790321 = 650^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212821 - 2² = 1212817 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1212821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14750 + ... + 14831.

It is an arithmetic number, because the mean of its divisors is an integer number (310611).

2^1212821 is an apocalyptic number.

It is an amenable number.

1212821 is a deficient number, since it is larger than the sum of its proper divisors (29623).

1212821 is an equidigital number, since it uses as much as digits as its factorization.

1212821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29622.

The product of its digits is 64, while the sum is 17.

The square root of 1212821 is about 1101.2815262230. The cubic root of 1212821 is about 106.6429710820.

Adding to 1212821 its reverse (1282121), we get a palindrome (2494942).

The spelling of 1212821 in words is "one million, two hundred twelve thousand, eight hundred twenty-one".