21406009699 has 2 divisors, whose sum is σ = 21406009700. Its totient is φ = 21406009698.

The previous prime is 21406009693. The next prime is 21406009721. The reversal of 21406009699 is 99690060412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21406009699 - 2²⁷ = 21271791971 is a prime.

It is not a weakly prime, because it can be changed into another prime (21406009693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10703004849 + 10703004850.

It is an arithmetic number, because the mean of its divisors is an integer number (10703004850).

Almost surely, 2^21406009699 is an apocalyptic number.

21406009699 is a deficient number, since it is larger than the sum of its proper divisors (1).

21406009699 is an equidigital number, since it uses as much as digits as its factorization.

21406009699 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 209952, while the sum is 46.

The spelling of 21406009699 in words is "twenty-one billion, four hundred six million, nine thousand, six hundred ninety-nine".