21000099959 has 2 divisors, whose sum is σ = 21000099960. Its totient is φ = 21000099958.

The previous prime is 21000099941. The next prime is 21000099973. The reversal of 21000099959 is 95999000012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000099959 - 2¹⁶ = 21000034423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000099359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500049979 + 10500049980.

It is an arithmetic number, because the mean of its divisors is an integer number (10500049980).

Almost surely, 2^21000099959 is an apocalyptic number.

21000099959 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000099959 is an equidigital number, since it uses as much as digits as its factorization.

21000099959 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 65610, while the sum is 44.

The spelling of 21000099959 in words is "twenty-one billion, ninety-nine thousand, nine hundred fifty-nine".