20543431 has 2 divisors, whose sum is σ = 20543432. Its totient is φ = 20543430.

The previous prime is 20543417. The next prime is 20543443. The reversal of 20543431 is 13434502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20543431 - 2¹¹ = 20541383 is a prime.

It is a super-2 number, since 2×20543431² = 844065114503522, which contains 22 as substring.

It is a Chen prime.

It is equal to p_1302835 and since 20543431 and 1302835 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20543401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10271715 + 10271716.

It is an arithmetic number, because the mean of its divisors is an integer number (10271716).

Almost surely, 2^20543431 is an apocalyptic number.

20543431 is a deficient number, since it is larger than the sum of its proper divisors (1).

20543431 is an equidigital number, since it uses as much as digits as its factorization.

20543431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 20543431 is about 4532.4861831008. The cubic root of 20543431 is about 273.8783225521.

Adding to 20543431 its reverse (13434502), we get a palindrome (33977933).

The spelling of 20543431 in words is "twenty million, five hundred forty-three thousand, four hundred thirty-one".