21255680911 has 2 divisors, whose sum is σ = 21255680912. Its totient is φ = 21255680910.

The previous prime is 21255680827. The next prime is 21255680917. The reversal of 21255680911 is 11908655212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21255680911 - 2¹¹ = 21255678863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21255680917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627840455 + 10627840456.

It is an arithmetic number, because the mean of its divisors is an integer number (10627840456).

Almost surely, 2^21255680911 is an apocalyptic number.

21255680911 is a deficient number, since it is larger than the sum of its proper divisors (1).

21255680911 is an equidigital number, since it uses as much as digits as its factorization.

21255680911 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43200, while the sum is 40.

The spelling of 21255680911 in words is "twenty-one billion, two hundred fifty-five million, six hundred eighty thousand, nine hundred eleven".