21020419993 has 2 divisors, whose sum is σ = 21020419994. Its totient is φ = 21020419992.

The previous prime is 21020419991. The next prime is 21020420023. The reversal of 21020419993 is 39991402012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11613941824 + 9406478169 = 107768^2 + 96987^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020419993 - 2¹ = 21020419991 is a prime.

It is a super-2 number, since 2×21020419993² (a number of 21 digits) contains 22 as substring.

Together with 21020419991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21020419991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510209996 + 10510209997.

It is an arithmetic number, because the mean of its divisors is an integer number (10510209997).

Almost surely, 2^21020419993 is an apocalyptic number.

It is an amenable number.

21020419993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020419993 is an equidigital number, since it uses as much as digits as its factorization.

21020419993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 40.

The spelling of 21020419993 in words is "twenty-one billion, twenty million, four hundred nineteen thousand, nine hundred ninety-three".