21631643927 has 2 divisors, whose sum is σ = 21631643928. Its totient is φ = 21631643926.

The previous prime is 21631643881. The next prime is 21631643933. The reversal of 21631643927 is 72934613612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21631643927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21631643987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10815821963 + 10815821964.

It is an arithmetic number, because the mean of its divisors is an integer number (10815821964).

Almost surely, 2^21631643927 is an apocalyptic number.

21631643927 is a deficient number, since it is larger than the sum of its proper divisors (1).

21631643927 is an equidigital number, since it uses as much as digits as its factorization.

21631643927 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 44.

The spelling of 21631643927 in words is "twenty-one billion, six hundred thirty-one million, six hundred forty-three thousand, nine hundred twenty-seven".