21107775551 has 2 divisors, whose sum is σ = 21107775552. Its totient is φ = 21107775550.

The previous prime is 21107775511. The next prime is 21107775589. The reversal of 21107775551 is 15557770112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21107775551 is a prime.

It is a super-2 number, since 2×21107775551² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21107775499 and 21107775508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21107775511) 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, 10553887775 + 10553887776.

It is an arithmetic number, because the mean of its divisors is an integer number (10553887776).

Almost surely, 2^21107775551 is an apocalyptic number.

21107775551 is a deficient number, since it is larger than the sum of its proper divisors (1).

21107775551 is an equidigital number, since it uses as much as digits as its factorization.

21107775551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 85750, while the sum is 41.

The spelling of 21107775551 in words is "twenty-one billion, one hundred seven million, seven hundred seventy-five thousand, five hundred fifty-one".