21135901 has 2 divisors, whose sum is σ = 21135902. Its totient is φ = 21135900.

The previous prime is 21135889. The next prime is 21135911. The reversal of 21135901 is 10953112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20884900 + 251001 = 4570^2 + 501^2 .

It is a cyclic number.

It is not a de Polignac number, because 21135901 - 2⁷ = 21135773 is a prime.

It is a super-2 number, since 2×21135901² = 893452622163602, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21135911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10567950 + 10567951.

It is an arithmetic number, because the mean of its divisors is an integer number (10567951).

Almost surely, 2^21135901 is an apocalyptic number.

It is an amenable number.

21135901 is a deficient number, since it is larger than the sum of its proper divisors (1).

21135901 is an equidigital number, since it uses as much as digits as its factorization.

21135901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 21135901 is about 4597.3797972323. The cubic root of 21135901 is about 276.4862821517.

The spelling of 21135901 in words is "twenty-one million, one hundred thirty-five thousand, nine hundred one".