9018751981 has 2 divisors, whose sum is σ = 9018751982. Its totient is φ = 9018751980.

The previous prime is 9018751969. The next prime is 9018751993. The reversal of 9018751981 is 1891578109.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (9018751969) and next prime (9018751993).

It can be written as a sum of positive squares in only one way, i.e., 6261556900 + 2757195081 = 79130^2 + 52509^2 .

It is a cyclic number.

It is not a de Polignac number, because 9018751981 - 2³¹ = 6871268333 is a prime.

It is a super-2 number, since 2×9018751981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9018751921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4509375990 + 4509375991.

It is an arithmetic number, because the mean of its divisors is an integer number (4509375991).

Almost surely, 2^9018751981 is an apocalyptic number.

It is an amenable number.

9018751981 is a deficient number, since it is larger than the sum of its proper divisors (1).

9018751981 is an equidigital number, since it uses as much as digits as its factorization.

9018751981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 49.

The square root of 9018751981 is about 94967.1099960402. The cubic root of 9018751981 is about 2081.5274761443.

The spelling of 9018751981 in words is "nine billion, eighteen million, seven hundred fifty-one thousand, nine hundred eighty-one".