21313207 has 2 divisors, whose sum is σ = 21313208. Its totient is φ = 21313206.

The previous prime is 21313199. The next prime is 21313241. The reversal of 21313207 is 70231312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21313207 - 2³ = 21313199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21313247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656603 + 10656604.

It is an arithmetic number, because the mean of its divisors is an integer number (10656604).

Almost surely, 2^21313207 is an apocalyptic number.

21313207 is a deficient number, since it is larger than the sum of its proper divisors (1).

21313207 is an equidigital number, since it uses as much as digits as its factorization.

21313207 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 19.

The square root of 21313207 is about 4616.6228999129. The cubic root of 21313207 is about 277.2572646724.

Adding to 21313207 its reverse (70231312), we get a palindrome (91544519).

The spelling of 21313207 in words is "twenty-one million, three hundred thirteen thousand, two hundred seven".