9042090721 has 2 divisors, whose sum is σ = 9042090722. Its totient is φ = 9042090720.

The previous prime is 9042090719. The next prime is 9042090787. The reversal of 9042090721 is 1270902409.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8698173696 + 343917025 = 93264^2 + 18545^2 .

It is a cyclic number.

It is not a de Polignac number, because 9042090721 - 2¹ = 9042090719 is a prime.

Together with 9042090719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (9042090121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4521045360 + 4521045361.

It is an arithmetic number, because the mean of its divisors is an integer number (4521045361).

Almost surely, 2^9042090721 is an apocalyptic number.

It is an amenable number.

9042090721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9042090721 is an equidigital number, since it uses as much as digits as its factorization.

9042090721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 9042090721 is about 95089.9086181073. The cubic root of 9042090721 is about 2083.3214561940.

The spelling of 9042090721 in words is "nine billion, forty-two million, ninety thousand, seven hundred twenty-one".