21045907 has 2 divisors, whose sum is σ = 21045908. Its totient is φ = 21045906.

The previous prime is 21045889. The next prime is 21045917. The reversal of 21045907 is 70954012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21045907 is a prime.

It is not a weakly prime, because it can be changed into another prime (21045917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522953 + 10522954.

It is an arithmetic number, because the mean of its divisors is an integer number (10522954).

Almost surely, 2^21045907 is an apocalyptic number.

21045907 is a deficient number, since it is larger than the sum of its proper divisors (1).

21045907 is an equidigital number, since it uses as much as digits as its factorization.

21045907 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21045907 is about 4587.5818248833. The cubic root of 21045907 is about 276.0933093105.

Adding to 21045907 its reverse (70954012), we get a palindrome (91999919).

It can be divided in two parts, 21045 and 907, that added together give a cube (21952 = 28³).

The spelling of 21045907 in words is "twenty-one million, forty-five thousand, nine hundred seven".