21203326691 has 2 divisors, whose sum is σ = 21203326692. Its totient is φ = 21203326690.

The previous prime is 21203326679. The next prime is 21203326847. The reversal of 21203326691 is 19662330212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21203326691 is a prime.

It is not a weakly prime, because it can be changed into another prime (21203326591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601663345 + 10601663346.

It is an arithmetic number, because the mean of its divisors is an integer number (10601663346).

Almost surely, 2^21203326691 is an apocalyptic number.

21203326691 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203326691 is an equidigital number, since it uses as much as digits as its factorization.

21203326691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 35.

The spelling of 21203326691 in words is "twenty-one billion, two hundred three million, three hundred twenty-six thousand, six hundred ninety-one".