21265001 has 2 divisors, whose sum is σ = 21265002. Its totient is φ = 21265000.

The previous prime is 21264979. The next prime is 21265043. The reversal of 21265001 is 10056212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10896601 + 10368400 = 3301^2 + 3220^2 .

It is a cyclic number.

It is not a de Polignac number, because 21265001 - 2¹⁸ = 21002857 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21265051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10632500 + 10632501.

It is an arithmetic number, because the mean of its divisors is an integer number (10632501).

Almost surely, 2^21265001 is an apocalyptic number.

It is an amenable number.

21265001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21265001 is an equidigital number, since it uses as much as digits as its factorization.

21265001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21265001 is about 4611.3990284945. The cubic root of 21265001 is about 277.0480743019.

The spelling of 21265001 in words is "twenty-one million, two hundred sixty-five thousand, one".