1123517821 has 2 divisors, whose sum is σ = 1123517822. Its totient is φ = 1123517820.

The previous prime is 1123517753. The next prime is 1123517849. The reversal of 1123517821 is 1287153211.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 595896921 + 527620900 = 24411^2 + 22970^2 .

It is a cyclic number.

It is not a de Polignac number, because 1123517821 - 2⁷ = 1123517693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1123517851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 561758910 + 561758911.

It is an arithmetic number, because the mean of its divisors is an integer number (561758911).

Almost surely, 2^1123517821 is an apocalyptic number.

It is an amenable number.

1123517821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1123517821 is an equidigital number, since it uses as much as digits as its factorization.

1123517821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3360, while the sum is 31.

The square root of 1123517821 is about 33518.9173602012. The cubic root of 1123517821 is about 1039.5849616711.

The spelling of 1123517821 in words is "one billion, one hundred twenty-three million, five hundred seventeen thousand, eight hundred twenty-one".