9001019981 has 2 divisors, whose sum is σ = 9001019982. Its totient is φ = 9001019980.

The previous prime is 9001019957. The next prime is 9001020001. The reversal of 9001019981 is 1899101009.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6898797481 + 2102222500 = 83059^2 + 45850^2 .

It is a cyclic number.

It is not a de Polignac number, because 9001019981 - 2⁶ = 9001019917 is a prime.

It is a super-2 number, since 2×9001019981² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9001019581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4500509990 + 4500509991.

It is an arithmetic number, because the mean of its divisors is an integer number (4500509991).

Almost surely, 2^9001019981 is an apocalyptic number.

It is an amenable number.

9001019981 is a deficient number, since it is larger than the sum of its proper divisors (1).

9001019981 is an equidigital number, since it uses as much as digits as its factorization.

9001019981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 38.

The square root of 9001019981 is about 94873.7054246328. The cubic root of 9001019981 is about 2080.1623995643.

The spelling of 9001019981 in words is "nine billion, one million, nineteen thousand, nine hundred eighty-one".