20733561 has 6 divisors (see below), whose sum is σ = 29948490. Its totient is φ = 13822368.

The previous prime is 20733553. The next prime is 20733563. The reversal of 20733561 is 16533702.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18870336 + 1863225 = 4344^2 + 1365^2 .

It is not a de Polignac number, because 20733561 - 2³ = 20733553 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20733563) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1151856 + ... + 1151873.

It is an arithmetic number, because the mean of its divisors is an integer number (4991415).

Almost surely, 2^20733561 is an apocalyptic number.

It is an amenable number.

20733561 is a deficient number, since it is larger than the sum of its proper divisors (9214929).

20733561 is a wasteful number, since it uses less digits than its factorization.

20733561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2303735 (or 2303732 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 27.

The square root of 20733561 is about 4553.4120173777. The cubic root of 20733561 is about 274.7206463474.

The spelling of 20733561 in words is "twenty million, seven hundred thirty-three thousand, five hundred sixty-one".