21415307 has 2 divisors, whose sum is σ = 21415308. Its totient is φ = 21415306.

The previous prime is 21415249. The next prime is 21415319. The reversal of 21415307 is 70351412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21415307 - 2¹⁸ = 21153163 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21415357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10707653 + 10707654.

It is an arithmetic number, because the mean of its divisors is an integer number (10707654).

Almost surely, 2^21415307 is an apocalyptic number.

21415307 is a deficient number, since it is larger than the sum of its proper divisors (1).

21415307 is an equidigital number, since it uses as much as digits as its factorization.

21415307 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21415307 is about 4627.6675550433. The cubic root of 21415307 is about 277.6992892497.

Adding to 21415307 its reverse (70351412), we get a palindrome (91766719).

The spelling of 21415307 in words is "twenty-one million, four hundred fifteen thousand, three hundred seven".