20431356 has 48 divisors (see below), whose sum is σ = 53695488. Its totient is φ = 5990400.

The previous prime is 20431343. The next prime is 20431381. The reversal of 20431356 is 65313402.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1596 + ... + 6588.

It is an arithmetic number, because the mean of its divisors is an integer number (1118656).

Almost surely, 2^20431356 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20431356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26847744).

20431356 is an abundant number, since it is smaller than the sum of its proper divisors (33264132).

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

20431356 is a wasteful number, since it uses less digits than its factorization.

20431356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5042 (or 5040 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 20431356 is about 4520.1057509753. The cubic root of 20431356 is about 273.3793649753.

Adding to 20431356 its reverse (65313402), we get a palindrome (85744758).

The spelling of 20431356 in words is "twenty million, four hundred thirty-one thousand, three hundred fifty-six".