1131212821 has 2 divisors, whose sum is σ = 1131212822. Its totient is φ = 1131212820.

The previous prime is 1131212783. The next prime is 1131212839. The reversal of 1131212821 is 1282121311.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 978813796 + 152399025 = 31286^2 + 12345^2 .

It is a cyclic number.

It is not a de Polignac number, because 1131212821 - 2¹³ = 1131204629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1131212792 and 1131212801.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1131212851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 565606410 + 565606411.

It is an arithmetic number, because the mean of its divisors is an integer number (565606411).

Almost surely, 2^1131212821 is an apocalyptic number.

It is an amenable number.

1131212821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1131212821 is an equidigital number, since it uses as much as digits as its factorization.

1131212821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 22.

The square root of 1131212821 is about 33633.5074144818. The cubic root of 1131212821 is about 1041.9529443717.

The spelling of 1131212821 in words is "one billion, one hundred thirty-one million, two hundred twelve thousand, eight hundred twenty-one".