900110021 has 2 divisors, whose sum is σ = 900110022. Its totient is φ = 900110020.

The previous prime is 900110011. The next prime is 900110027. The reversal of 900110021 is 120011009.

900110021 = 21214² + 21215².

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 450076225 + 450033796 = 21215^2 + 21214^2 .

It is an emirp because it is prime and its reverse (120011009) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 900110021 - 2⁶ = 900109957 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 900109978 and 900110005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (900110027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 450055010 + 450055011.

It is an arithmetic number, because the mean of its divisors is an integer number (450055011).

Almost surely, 2^900110021 is an apocalyptic number.

900110021 is the 21215-th centered square number.

It is an amenable number.

900110021 is a deficient number, since it is larger than the sum of its proper divisors (1).

900110021 is an equidigital number, since it uses as much as digits as its factorization.

900110021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18, while the sum is 14.

The square root of 900110021 is about 30001.8336272968. The cubic root of 900110021 is about 965.5287252647.

The spelling of 900110021 in words is "nine hundred million, one hundred ten thousand, twenty-one".