20133661 has 8 divisors (see below), whose sum is σ = 21894840. Its totient is φ = 18436608.

The previous prime is 20133649. The next prime is 20133677. The reversal of 20133661 is 16633102.

It can be written as a sum of positive squares in 4 ways, for example, as 2869636 + 17264025 = 1694^2 + 4155^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20133661 - 2⁵ = 20133629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20133961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15376 + ... + 16633.

It is an arithmetic number, because the mean of its divisors is an integer number (2736855).

Almost surely, 2^20133661 is an apocalyptic number.

It is an amenable number.

20133661 is a deficient number, since it is larger than the sum of its proper divisors (1761179).

20133661 is a wasteful number, since it uses less digits than its factorization.

20133661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32063.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 20133661 is about 4487.0548247152. The cubic root of 20133661 is about 272.0451058775.

Adding to 20133661 its reverse (16633102), we get a palindrome (36766763).

The spelling of 20133661 in words is "twenty million, one hundred thirty-three thousand, six hundred sixty-one".