21003707 has 2 divisors, whose sum is σ = 21003708. Its totient is φ = 21003706.

The previous prime is 21003677. The next prime is 21003713. The reversal of 21003707 is 70730012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21003707 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21003727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501853 + 10501854.

It is an arithmetic number, because the mean of its divisors is an integer number (10501854).

Almost surely, 2^21003707 is an apocalyptic number.

21003707 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003707 is an equidigital number, since it uses as much as digits as its factorization.

21003707 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 294, while the sum is 20.

The square root of 21003707 is about 4582.9801439675. The cubic root of 21003707 is about 275.9086505432.

Adding to 21003707 its reverse (70730012), we get a palindrome (91733719).

The spelling of 21003707 in words is "twenty-one million, three thousand, seven hundred seven".