1156816021 has 2 divisors, whose sum is σ = 1156816022. Its totient is φ = 1156816020.

The previous prime is 1156815997. The next prime is 1156816043. The reversal of 1156816021 is 1206186511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1154300625 + 2515396 = 33975^2 + 1586^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1156816021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1156816091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 578408010 + 578408011.

It is an arithmetic number, because the mean of its divisors is an integer number (578408011).

Almost surely, 2^1156816021 is an apocalyptic number.

It is an amenable number.

1156816021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1156816021 is an equidigital number, since it uses as much as digits as its factorization.

1156816021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 1156816021 is about 34011.9981918146. The cubic root of 1156816021 is about 1049.7553537359.

The spelling of 1156816021 in words is "one billion, one hundred fifty-six million, eight hundred sixteen thousand, twenty-one".