21215440307 has 2 divisors, whose sum is σ = 21215440308. Its totient is φ = 21215440306.

The previous prime is 21215440231. The next prime is 21215440357. The reversal of 21215440307 is 70304451212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21215440307 - 2¹⁰ = 21215439283 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21215440307.

It is not a weakly prime, because it can be changed into another prime (21215440357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10607720153 + 10607720154.

It is an arithmetic number, because the mean of its divisors is an integer number (10607720154).

Almost surely, 2^21215440307 is an apocalyptic number.

21215440307 is a deficient number, since it is larger than the sum of its proper divisors (1).

21215440307 is an equidigital number, since it uses as much as digits as its factorization.

21215440307 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6720, while the sum is 29.

Adding to 21215440307 its reverse (70304451212), we get a palindrome (91519891519).

The spelling of 21215440307 in words is "twenty-one billion, two hundred fifteen million, four hundred forty thousand, three hundred seven".