21302503993 has 2 divisors, whose sum is σ = 21302503994. Its totient is φ = 21302503992.

The previous prime is 21302503991. The next prime is 21302504011. The reversal of 21302503993 is 39930520312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13846699584 + 7455804409 = 117672^2 + 86347^2 .

It is a cyclic number.

It is not a de Polignac number, because 21302503993 - 2¹ = 21302503991 is a prime.

Together with 21302503991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21302503991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10651251996 + 10651251997.

It is an arithmetic number, because the mean of its divisors is an integer number (10651251997).

Almost surely, 2^21302503993 is an apocalyptic number.

It is an amenable number.

21302503993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21302503993 is an equidigital number, since it uses as much as digits as its factorization.

21302503993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43740, while the sum is 37.

The spelling of 21302503993 in words is "twenty-one billion, three hundred two million, five hundred three thousand, nine hundred ninety-three".