21012115099 has 2 divisors, whose sum is σ = 21012115100. Its totient is φ = 21012115098.

The previous prime is 21012115027. The next prime is 21012115147. The reversal of 21012115099 is 99051121012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21012115099 - 2⁹ = 21012114587 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21012115099.

It is not a weakly prime, because it can be changed into another prime (21012115009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506057549 + 10506057550.

It is an arithmetic number, because the mean of its divisors is an integer number (10506057550).

Almost surely, 2^21012115099 is an apocalyptic number.

21012115099 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012115099 is an equidigital number, since it uses as much as digits as its factorization.

21012115099 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 31.

The spelling of 21012115099 in words is "twenty-one billion, twelve million, one hundred fifteen thousand, ninety-nine".