21033949009 has 2 divisors, whose sum is σ = 21033949010. Its totient is φ = 21033949008.

The previous prime is 21033948967. The next prime is 21033949043. The reversal of 21033949009 is 90094933012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19851964609 + 1181984400 = 140897^2 + 34380^2 .

It is a cyclic number.

It is not a de Polignac number, because 21033949009 - 2²⁵ = 21000394577 is a prime.

It is not a weakly prime, because it can be changed into another prime (21033949309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10516974504 + 10516974505.

It is an arithmetic number, because the mean of its divisors is an integer number (10516974505).

Almost surely, 2^21033949009 is an apocalyptic number.

It is an amenable number.

21033949009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21033949009 is an equidigital number, since it uses as much as digits as its factorization.

21033949009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 40.

The spelling of 21033949009 in words is "twenty-one billion, thirty-three million, nine hundred forty-nine thousand, nine".