1211921 has 2 divisors, whose sum is σ = 1211922. Its totient is φ = 1211920.

The previous prime is 1211911. The next prime is 1211923. The reversal of 1211921 is 1291121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1081600 + 130321 = 1040^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211921 - 2⁶ = 1211857 is a prime.

Together with 1211923, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211921.

It is not a weakly prime, because it can be changed into another prime (1211923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605960 + 605961.

It is an arithmetic number, because the mean of its divisors is an integer number (605961).

2^1211921 is an apocalyptic number.

It is an amenable number.

1211921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211921 is an equidigital number, since it uses as much as digits as its factorization.

1211921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36, while the sum is 17.

The square root of 1211921 is about 1100.8728355264. The cubic root of 1211921 is about 106.6165856481.

The spelling of 1211921 in words is "one million, two hundred eleven thousand, nine hundred twenty-one".