20418157 has 2 divisors, whose sum is σ = 20418158. Its totient is φ = 20418156.

The previous prime is 20418137. The next prime is 20418161. The reversal of 20418157 is 75181402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16924996 + 3493161 = 4114^2 + 1869^2 .

It is a cyclic number.

It is not a de Polignac number, because 20418157 - 2¹⁵ = 20385389 is a prime.

It is a super-2 number, since 2×20418157² = 833802270553298, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20418137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10209078 + 10209079.

It is an arithmetic number, because the mean of its divisors is an integer number (10209079).

Almost surely, 2^20418157 is an apocalyptic number.

It is an amenable number.

20418157 is a deficient number, since it is larger than the sum of its proper divisors (1).

20418157 is an equidigital number, since it uses as much as digits as its factorization.

20418157 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 20418157 is about 4518.6454828853. The cubic root of 20418157 is about 273.3204830696.

Adding to 20418157 its reverse (75181402), we get a palindrome (95599559).

The spelling of 20418157 in words is "twenty million, four hundred eighteen thousand, one hundred fifty-seven".