21245707 has 16 divisors (see below), whose sum is σ = 24893440. Its totient is φ = 17757792.

The previous prime is 21245683. The next prime is 21245713. The reversal of 21245707 is 70754212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21245707 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21245737) 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 15 ways as a sum of consecutive naturals, for example, 56773 + ... + 57145.

It is an arithmetic number, because the mean of its divisors is an integer number (1555840).

Almost surely, 2^21245707 is an apocalyptic number.

21245707 is a deficient number, since it is larger than the sum of its proper divisors (3647733).

21245707 is a wasteful number, since it uses less digits than its factorization.

21245707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 562.

The product of its (nonzero) digits is 3920, while the sum is 28.

The square root of 21245707 is about 4609.3065638987. The cubic root of 21245707 is about 276.9642592263.

Adding to 21245707 its reverse (70754212), we get a palindrome (91999919).

It can be divided in two parts, 21245 and 707, that added together give a cube (21952 = 28³).

The spelling of 21245707 in words is "twenty-one million, two hundred forty-five thousand, seven hundred seven".