21111005693 has 2 divisors, whose sum is σ = 21111005694. Its totient is φ = 21111005692.

The previous prime is 21111005647. The next prime is 21111005717. The reversal of 21111005693 is 39650011112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12977310724 + 8133694969 = 113918^2 + 90187^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111005693 - 2²⁶ = 21043896829 is a prime.

It is a super-2 number, since 2×21111005693² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111005623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555502846 + 10555502847.

It is an arithmetic number, because the mean of its divisors is an integer number (10555502847).

Almost surely, 2^21111005693 is an apocalyptic number.

It is an amenable number.

21111005693 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111005693 is an equidigital number, since it uses as much as digits as its factorization.

21111005693 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 29.

The spelling of 21111005693 in words is "twenty-one billion, one hundred eleven million, five thousand, six hundred ninety-three".