21010220993 has 2 divisors, whose sum is σ = 21010220994. Its totient is φ = 21010220992.

The previous prime is 21010220983. The next prime is 21010220999. The reversal of 21010220993 is 39902201012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10797703744 + 10212517249 = 103912^2 + 101057^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010220993 - 2¹⁴ = 21010204609 is a prime.

It is a super-3 number, since 3×21010220993³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21010220999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505110496 + 10505110497.

It is an arithmetic number, because the mean of its divisors is an integer number (10505110497).

Almost surely, 2^21010220993 is an apocalyptic number.

It is an amenable number.

21010220993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010220993 is an equidigital number, since it uses as much as digits as its factorization.

21010220993 is an evil number, because the sum of its binary digits is even.

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

The spelling of 21010220993 in words is "twenty-one billion, ten million, two hundred twenty thousand, nine hundred ninety-three".