21004202993 has 2 divisors, whose sum is σ = 21004202994. Its totient is φ = 21004202992.

The previous prime is 21004202987. The next prime is 21004203029. The reversal of 21004202993 is 39920240012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17852166544 + 3152036449 = 133612^2 + 56143^2 .

It is a cyclic number.

It is not a de Polignac number, because 21004202993 - 2⁴ = 21004202977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21004202903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502101496 + 10502101497.

It is an arithmetic number, because the mean of its divisors is an integer number (10502101497).

Almost surely, 2^21004202993 is an apocalyptic number.

It is an amenable number.

21004202993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004202993 is an equidigital number, since it uses as much as digits as its factorization.

21004202993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 32.

The spelling of 21004202993 in words is "twenty-one billion, four million, two hundred two thousand, nine hundred ninety-three".