21006440927 has 2 divisors, whose sum is σ = 21006440928. Its totient is φ = 21006440926.

The previous prime is 21006440911. The next prime is 21006440947. The reversal of 21006440927 is 72904460012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21006440927 - 2⁴ = 21006440911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21006440947) 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, 10503220463 + 10503220464.

It is an arithmetic number, because the mean of its divisors is an integer number (10503220464).

Almost surely, 2^21006440927 is an apocalyptic number.

21006440927 is a deficient number, since it is larger than the sum of its proper divisors (1).

21006440927 is an equidigital number, since it uses as much as digits as its factorization.

21006440927 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 35.

The spelling of 21006440927 in words is "twenty-one billion, six million, four hundred forty thousand, nine hundred twenty-seven".