20431340 has 24 divisors (see below), whose sum is σ = 43611792. Its totient is φ = 8038080.

The previous prime is 20431319. The next prime is 20431343. The reversal of 20431340 is 4313402.

It is not an unprimeable number, because it can be changed into a prime (20431343) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7154 + ... + 9593.

It is an arithmetic number, because the mean of its divisors is an integer number (1817158).

Almost surely, 2^20431340 is an apocalyptic number.

20431340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20431340 is an abundant number, since it is smaller than the sum of its proper divisors (23180452).

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

20431340 is a wasteful number, since it uses less digits than its factorization.

20431340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16817 (or 16815 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 20431340 is about 4520.1039811049. The cubic root of 20431340 is about 273.3792936133.

Adding to 20431340 its reverse (4313402), we get a palindrome (24744742).

The spelling of 20431340 in words is "twenty million, four hundred thirty-one thousand, three hundred forty".