21157773658563 has 16 divisors (see below), whose sum is σ = 28283507163296. Its totient is φ = 14068629711360.

The previous prime is 21157773658523. The next prime is 21157773658579. The reversal of 21157773658563 is 36585637775112.

It is a Cunningham number, because it is equal to 4599758²-1.

It is not a de Polignac number, because 21157773658563 - 2⁶ = 21157773658499 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21157773658494 and 21157773658503.

It is not an unprimeable number, because it can be changed into a prime (21157773658523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2299881 + ... + 6899637.

It is an arithmetic number, because the mean of its divisors is an integer number (1767719197706).

Almost surely, 2^{21157773658563} is an apocalyptic number.

21157773658563 is a deficient number, since it is larger than the sum of its proper divisors (7125733504733).

21157773658563 is a wasteful number, since it uses less digits than its factorization.

21157773658563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4603734.

The product of its digits is 222264000, while the sum is 66.

The spelling of 21157773658563 in words is "twenty-one trillion, one hundred fifty-seven billion, seven hundred seventy-three million, six hundred fifty-eight thousand, five hundred sixty-three".