21145707 has 24 divisors (see below), whose sum is σ = 33546240. Its totient is φ = 12728880.

The previous prime is 21145699. The next prime is 21145741. The reversal of 21145707 is 70754112.

It is not a de Polignac number, because 21145707 - 2³ = 21145699 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21145757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15894 + ... + 17172.

It is an arithmetic number, because the mean of its divisors is an integer number (1397760).

Almost surely, 2^21145707 is an apocalyptic number.

21145707 is a deficient number, since it is larger than the sum of its proper divisors (12400533).

21145707 is a wasteful number, since it uses less digits than its factorization.

21145707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1463 (or 1460 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 21145707 is about 4598.4461506035. The cubic root of 21145707 is about 276.5290341388.

Adding to 21145707 its reverse (70754112), we get a palindrome (91899819).

The spelling of 21145707 in words is "twenty-one million, one hundred forty-five thousand, seven hundred seven".