20661633 has 12 divisors (see below), whose sum is σ = 29916900. Its totient is φ = 13741056.

The previous prime is 20661631. The next prime is 20661643. The reversal of 20661633 is 33616602.

20661633 is a `hidden beast` number, since 20 + 6 + 6 + 1 + 633 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 4717584 + 15944049 = 2172^2 + 3993^2 .

It is not a de Polignac number, because 20661633 - 2¹ = 20661631 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20661597 and 20661606.

It is not an unprimeable number, because it can be changed into a prime (20661631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1485 + ... + 6597.

It is an arithmetic number, because the mean of its divisors is an integer number (2493075).

Almost surely, 2^20661633 is an apocalyptic number.

It is an amenable number.

20661633 is a deficient number, since it is larger than the sum of its proper divisors (9255267).

20661633 is a wasteful number, since it uses less digits than its factorization.

20661633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5568 (or 5565 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 27.

The square root of 20661633 is about 4545.5069024257. The cubic root of 20661633 is about 274.4025951597.

The spelling of 20661633 in words is "twenty million, six hundred sixty-one thousand, six hundred thirty-three".