21235807 has 2 divisors, whose sum is σ = 21235808. Its totient is φ = 21235806.

The previous prime is 21235793. The next prime is 21235813. The reversal of 21235807 is 70853212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21235807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21235607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617903 + 10617904.

It is an arithmetic number, because the mean of its divisors is an integer number (10617904).

Almost surely, 2^21235807 is an apocalyptic number.

21235807 is a deficient number, since it is larger than the sum of its proper divisors (1).

21235807 is an equidigital number, since it uses as much as digits as its factorization.

21235807 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 21235807 is about 4608.2325245152. The cubic root of 21235807 is about 276.9212329313.

The spelling of 21235807 in words is "twenty-one million, two hundred thirty-five thousand, eight hundred seven".