21157661411 has 2 divisors, whose sum is σ = 21157661412. Its totient is φ = 21157661410.

The previous prime is 21157661387. The next prime is 21157661453. The reversal of 21157661411 is 11416675112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21157661411 - 2¹⁸ = 21157399267 is a prime.

It is not a weakly prime, because it can be changed into another prime (21157661461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10578830705 + 10578830706.

It is an arithmetic number, because the mean of its divisors is an integer number (10578830706).

Almost surely, 2^21157661411 is an apocalyptic number.

21157661411 is a deficient number, since it is larger than the sum of its proper divisors (1).

21157661411 is an equidigital number, since it uses as much as digits as its factorization.

21157661411 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 35.

The spelling of 21157661411 in words is "twenty-one billion, one hundred fifty-seven million, six hundred sixty-one thousand, four hundred eleven".