21757195511 has 2 divisors, whose sum is σ = 21757195512. Its totient is φ = 21757195510.

The previous prime is 21757195463. The next prime is 21757195541. The reversal of 21757195511 is 11559175712.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21757195511 is a prime.

It is a super-2 number, since 2×21757195511² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21757195541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10878597755 + 10878597756.

It is an arithmetic number, because the mean of its divisors is an integer number (10878597756).

Almost surely, 2^21757195511 is an apocalyptic number.

21757195511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21757195511 is an equidigital number, since it uses as much as digits as its factorization.

21757195511 is an evil number, because the sum of its binary digits is even.

The product of its digits is 110250, while the sum is 44.

The spelling of 21757195511 in words is "twenty-one billion, seven hundred fifty-seven million, one hundred ninety-five thousand, five hundred eleven".