21121534999 has 2 divisors, whose sum is σ = 21121535000. Its totient is φ = 21121534998.

The previous prime is 21121534981. The next prime is 21121535069. The reversal of 21121534999 is 99943512112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21121534999 - 2⁹ = 21121534487 is a prime.

It is a super-2 number, since 2×21121534999² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121534099) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560767499 + 10560767500.

It is an arithmetic number, because the mean of its divisors is an integer number (10560767500).

Almost surely, 2^21121534999 is an apocalyptic number.

21121534999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121534999 is an equidigital number, since it uses as much as digits as its factorization.

21121534999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 174960, while the sum is 46.

The spelling of 21121534999 in words is "twenty-one billion, one hundred twenty-one million, five hundred thirty-four thousand, nine hundred ninety-nine".