9100901981 has 2 divisors, whose sum is σ = 9100901982. Its totient is φ = 9100901980.

The previous prime is 9100901977. The next prime is 9100901983. The reversal of 9100901981 is 1891090019.

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., 6643717081 + 2457184900 = 81509^2 + 49570^2 .

It is a cyclic number.

It is not a de Polignac number, because 9100901981 - 2² = 9100901977 is a prime.

It is a super-2 number, since 2×9100901981² (a number of 21 digits) contains 22 as substring.

Together with 9100901983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9100901983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4550450990 + 4550450991.

It is an arithmetic number, because the mean of its divisors is an integer number (4550450991).

Almost surely, 2^9100901981 is an apocalyptic number.

It is an amenable number.

9100901981 is a deficient number, since it is larger than the sum of its proper divisors (1).

9100901981 is an equidigital number, since it uses as much as digits as its factorization.

9100901981 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 9100901981 is about 95398.6476895768. The cubic root of 9100901981 is about 2087.8284551165.

The spelling of 9100901981 in words is "nine billion, one hundred million, nine hundred one thousand, nine hundred eighty-one".