21268901 has 2 divisors, whose sum is σ = 21268902. Its totient is φ = 21268900.

The previous prime is 21268889. The next prime is 21268903. The reversal of 21268901 is 10986212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14638276 + 6630625 = 3826^2 + 2575^2 .

It is a cyclic number.

It is not a de Polignac number, because 21268901 - 2⁶ = 21268837 is a prime.

It is a super-2 number, since 2×21268901² = 904732299495602, which contains 22 as substring.

Together with 21268903, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21268903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10634450 + 10634451.

It is an arithmetic number, because the mean of its divisors is an integer number (10634451).

Almost surely, 2^21268901 is an apocalyptic number.

It is an amenable number.

21268901 is a deficient number, since it is larger than the sum of its proper divisors (1).

21268901 is an equidigital number, since it uses as much as digits as its factorization.

21268901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 21268901 is about 4611.8218742705. The cubic root of 21268901 is about 277.0650101337.

The spelling of 21268901 in words is "twenty-one million, two hundred sixty-eight thousand, nine hundred one".