1231146821 has 2 divisors, whose sum is σ = 1231146822. Its totient is φ = 1231146820.

The previous prime is 1231146799. The next prime is 1231146827. The reversal of 1231146821 is 1286411321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1210344100 + 20802721 = 34790^2 + 4561^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231146821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231146827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615573410 + 615573411.

It is an arithmetic number, because the mean of its divisors is an integer number (615573411).

Almost surely, 2^1231146821 is an apocalyptic number.

It is an amenable number.

1231146821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231146821 is an equidigital number, since it uses as much as digits as its factorization.

1231146821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 29.

The square root of 1231146821 is about 35087.7018483685. The cubic root of 1231146821 is about 1071.7741611977.

The spelling of 1231146821 in words is "one billion, two hundred thirty-one million, one hundred forty-six thousand, eight hundred twenty-one".