20431311 has 4 divisors (see below), whose sum is σ = 27241752. Its totient is φ = 13620872.

The previous prime is 20431309. The next prime is 20431319. The reversal of 20431311 is 11313402.

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

It is a cyclic number.

It is not a de Polignac number, because 20431311 - 2¹ = 20431309 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20431319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3405216 + ... + 3405221.

It is an arithmetic number, because the mean of its divisors is an integer number (6810438).

Almost surely, 2^20431311 is an apocalyptic number.

20431311 is a deficient number, since it is larger than the sum of its proper divisors (6810441).

20431311 is an equidigital number, since it uses as much as digits as its factorization.

20431311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6810440.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 20431311 is about 4520.1007732129. The cubic root of 20431311 is about 273.3791642694.

Adding to 20431311 its reverse (11313402), we get a palindrome (31744713).

The spelling of 20431311 in words is "twenty million, four hundred thirty-one thousand, three hundred eleven".