21393039403 has 2 divisors, whose sum is σ = 21393039404. Its totient is φ = 21393039402.

The previous prime is 21393039359. The next prime is 21393039407. The reversal of 21393039403 is 30493039312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21393039403 - 2¹⁷ = 21392908331 is a prime.

It is not a weakly prime, because it can be changed into another prime (21393039407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10696519701 + 10696519702.

It is an arithmetic number, because the mean of its divisors is an integer number (10696519702).

Almost surely, 2^21393039403 is an apocalyptic number.

21393039403 is a deficient number, since it is larger than the sum of its proper divisors (1).

21393039403 is an equidigital number, since it uses as much as digits as its factorization.

21393039403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 37.

Subtracting 21393039403 from its reverse (30493039312), we obtain a palindrome (9099999909).

The spelling of 21393039403 in words is "twenty-one billion, three hundred ninety-three million, thirty-nine thousand, four hundred three".