20634181 has 4 divisors (see below), whose sum is σ = 20748364. Its totient is φ = 20520000.

The previous prime is 20634161. The next prime is 20634217. The reversal of 20634181 is 18143602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18143602 = 2 ⋅9071801.

It can be written as a sum of positive squares in 2 ways, for example, as 5688225 + 14945956 = 2385^2 + 3866^2 .

It is a cyclic number.

It is not a de Polignac number, because 20634181 - 2¹⁹ = 20109893 is a prime.

It is a super-2 number, since 2×20634181² = 851538851081522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20634101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56820 + ... + 57181.

It is an arithmetic number, because the mean of its divisors is an integer number (5187091).

Almost surely, 2^20634181 is an apocalyptic number.

It is an amenable number.

20634181 is a deficient number, since it is larger than the sum of its proper divisors (114183).

20634181 is a wasteful number, since it uses less digits than its factorization.

20634181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114182.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 20634181 is about 4542.4862135179. The cubic root of 20634181 is about 274.2810133097.

Adding to 20634181 its reverse (18143602), we get a palindrome (38777783).

The spelling of 20634181 in words is "twenty million, six hundred thirty-four thousand, one hundred eighty-one".