21556604467 has 2 divisors, whose sum is σ = 21556604468. Its totient is φ = 21556604466.

The previous prime is 21556604449. The next prime is 21556604501. The reversal of 21556604467 is 76440665512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21556604467 - 2⁷ = 21556604339 is a prime.

It is a super-2 number, since 2×21556604467² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21556602467) 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, 10778302233 + 10778302234.

It is an arithmetic number, because the mean of its divisors is an integer number (10778302234).

Almost surely, 2^21556604467 is an apocalyptic number.

21556604467 is a deficient number, since it is larger than the sum of its proper divisors (1).

21556604467 is an equidigital number, since it uses as much as digits as its factorization.

21556604467 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1209600, while the sum is 46.

The spelling of 21556604467 in words is "twenty-one billion, five hundred fifty-six million, six hundred four thousand, four hundred sixty-seven".