21410009 has 2 divisors, whose sum is σ = 21410010. Its totient is φ = 21410008.

The previous prime is 21410003. The next prime is 21410023. The reversal of 21410009 is 90001412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13344409 + 8065600 = 3653^2 + 2840^2 .

It is a cyclic number.

It is not a de Polignac number, because 21410009 - 2¹⁶ = 21344473 is a prime.

It is not a weakly prime, because it can be changed into another prime (21410003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10705004 + 10705005.

It is an arithmetic number, because the mean of its divisors is an integer number (10705005).

Almost surely, 2^21410009 is an apocalyptic number.

It is an amenable number.

21410009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21410009 is an equidigital number, since it uses as much as digits as its factorization.

21410009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 21410009 is about 4627.0950930362. The cubic root of 21410009 is about 277.6763870614.

The spelling of 21410009 in words is "twenty-one million, four hundred ten thousand, nine".