21043740307 has 4 divisors (see below), whose sum is σ = 21169750896. Its totient is φ = 20917729720.

The previous prime is 21043740283. The next prime is 21043740329. The reversal of 21043740307 is 70304734012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21043740307 is a prime.

It is a super-2 number, since 2×21043740307² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21043740407) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63005044 + ... + 63005377.

It is an arithmetic number, because the mean of its divisors is an integer number (5292437724).

Almost surely, 2^21043740307 is an apocalyptic number.

21043740307 is a deficient number, since it is larger than the sum of its proper divisors (126010589).

21043740307 is a wasteful number, since it uses less digits than its factorization.

21043740307 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126010588.

The product of its (nonzero) digits is 14112, while the sum is 31.

The spelling of 21043740307 in words is "twenty-one billion, forty-three million, seven hundred forty thousand, three hundred seven".