20431380 has 48 divisors (see below), whose sum is σ = 57496320. Its totient is φ = 5420928.

The previous prime is 20431343. The next prime is 20431381. The reversal of 20431380 is 8313402.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20431381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12997 + ... + 14483.

It is an arithmetic number, because the mean of its divisors is an integer number (1197840).

Almost surely, 2^20431380 is an apocalyptic number.

20431380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20431380 is an abundant number, since it is smaller than the sum of its proper divisors (37064940).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20431380 is a wasteful number, since it uses less digits than its factorization.

20431380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1728 (or 1726 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 20431380 is about 4520.1084057797. The cubic root of 20431380 is about 273.3794720183.

Adding to 20431380 its reverse (8313402), we get a palindrome (28744782).

The spelling of 20431380 in words is "twenty million, four hundred thirty-one thousand, three hundred eighty".