20100645 has 24 divisors (see below), whose sum is σ = 34956792. Its totient is φ = 10684800.

The previous prime is 20100629. The next prime is 20100673. The reversal of 20100645 is 54600102.

It is a happy number.

20100645 is a `hidden beast` number, since 20 + 1 + 0 + 0 + 645 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 39204 + 20061441 = 198^2 + 4479^2 .

It is not a de Polignac number, because 20100645 - 2⁴ = 20100629 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18415 + ... + 19475.

It is an arithmetic number, because the mean of its divisors is an integer number (1456533).

Almost surely, 2^20100645 is an apocalyptic number.

It is an amenable number.

20100645 is a deficient number, since it is larger than the sum of its proper divisors (14856147).

20100645 is a wasteful number, since it uses less digits than its factorization.

20100645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1493 (or 1490 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20100645 is about 4483.3742872975. The cubic root of 20100645 is about 271.8963209597.

Adding to 20100645 its reverse (54600102), we get a palindrome (74700747).

The spelling of 20100645 in words is "twenty million, one hundred thousand, six hundred forty-five".