20011645 has 4 divisors (see below), whose sum is σ = 24013980. Its totient is φ = 16009312.

The previous prime is 20011631. The next prime is 20011657. The reversal of 20011645 is 54611002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3250809 + 16760836 = 1803^2 + 4094^2 .

It is a cyclic number.

It is not a de Polignac number, because 20011645 - 2¹¹ = 20009597 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2001160 + ... + 2001169.

It is an arithmetic number, because the mean of its divisors is an integer number (6003495).

Almost surely, 2^20011645 is an apocalyptic number.

It is an amenable number.

20011645 is a deficient number, since it is larger than the sum of its proper divisors (4002335).

20011645 is an equidigital number, since it uses as much as digits as its factorization.

20011645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4002334.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 20011645 is about 4473.4377161194. The cubic root of 20011645 is about 271.4944337599.

Adding to 20011645 its reverse (54611002), we get a palindrome (74622647).

The spelling of 20011645 in words is "twenty million, eleven thousand, six hundred forty-five".