1121720813 has 2 divisors, whose sum is σ = 1121720814. Its totient is φ = 1121720812.

The previous prime is 1121720801. The next prime is 1121720837. The reversal of 1121720813 is 3180271211.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1113757129 + 7963684 = 33373^2 + 2822^2 .

It is a cyclic number.

It is not a de Polignac number, because 1121720813 - 2¹⁴ = 1121704429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1121120813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 560860406 + 560860407.

It is an arithmetic number, because the mean of its divisors is an integer number (560860407).

Almost surely, 2^1121720813 is an apocalyptic number.

It is an amenable number.

1121720813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1121720813 is an equidigital number, since it uses as much as digits as its factorization.

1121720813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 26.

The square root of 1121720813 is about 33492.1007552527. The cubic root of 1121720813 is about 1039.0304119812.

The spelling of 1121720813 in words is "one billion, one hundred twenty-one million, seven hundred twenty thousand, eight hundred thirteen".