21020210993 has 8 divisors (see below), whose sum is σ = 21536723880. Its totient is φ = 20503880320.

The previous prime is 21020210963. The next prime is 21020211011. The reversal of 21020210993 is 39901202012.

It can be written as a sum of positive squares in 4 ways, for example, as 1712552689 + 19307658304 = 41383^2 + 138952^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21020210993 - 2¹⁶ = 21020145457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020210923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 204671 + ... + 289707.

It is an arithmetic number, because the mean of its divisors is an integer number (2692090485).

Almost surely, 2^21020210993 is an apocalyptic number.

It is an amenable number.

21020210993 is a deficient number, since it is larger than the sum of its proper divisors (516512887).

21020210993 is an equidigital number, since it uses as much as digits as its factorization.

21020210993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91107.

The product of its (nonzero) digits is 1944, while the sum is 29.

The spelling of 21020210993 in words is "twenty-one billion, twenty million, two hundred ten thousand, nine hundred ninety-three".