21166552053 has 12 divisors (see below), whose sum is σ = 30575503660. Its totient is φ = 14110298496.

The previous prime is 21166552039. The next prime is 21166552061. The reversal of 21166552053 is 35025566112.

21166552053 is a `hidden beast` number, since 21 + 1 + 6 + 65 + 520 + 53 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3884031684 + 17282520369 = 62322^2 + 131463^2 .

It is not a de Polignac number, because 21166552053 - 2¹² = 21166547957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21166551999 and 21166552017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21166552013) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 164493 + ... + 263421.

Almost surely, 2^21166552053 is an apocalyptic number.

It is an amenable number.

21166552053 is a deficient number, since it is larger than the sum of its proper divisors (9408951607).

21166552053 is a wasteful number, since it uses less digits than its factorization.

21166552053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122708 (or 122705 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The spelling of 21166552053 in words is "twenty-one billion, one hundred sixty-six million, five hundred fifty-two thousand, fifty-three".