21025313 has 2 divisors, whose sum is σ = 21025314. Its totient is φ = 21025312.

The previous prime is 21025307. The next prime is 21025321. The reversal of 21025313 is 31352012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15904144 + 5121169 = 3988^2 + 2263^2 .

It is a cyclic number.

It is not a de Polignac number, because 21025313 - 2¹⁶ = 20959777 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21025291 and 21025300.

It is not a weakly prime, because it can be changed into another prime (21025363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10512656 + 10512657.

It is an arithmetic number, because the mean of its divisors is an integer number (10512657).

Almost surely, 2^21025313 is an apocalyptic number.

It is an amenable number.

21025313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21025313 is an equidigital number, since it uses as much as digits as its factorization.

21025313 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21025313 is about 4585.3367379070. The cubic root of 21025313 is about 276.0032249501.

Adding to 21025313 its reverse (31352012), we get a palindrome (52377325).

The spelling of 21025313 in words is "twenty-one million, twenty-five thousand, three hundred thirteen".