20131320440 has 128 divisors (see below), whose sum is σ = 59794329600. Its totient is φ = 5905582080.

The previous prime is 20131320421. The next prime is 20131320479. The reversal of 20131320440 is 4402313102.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 139880 + ... + 244599.

It is an arithmetic number, because the mean of its divisors is an integer number (467143200).

Almost surely, 2^20131320440 is an apocalyptic number.

20131320440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20131320440 is an abundant number, since it is smaller than the sum of its proper divisors (39663009160).

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

20131320440 is a wasteful number, since it uses less digits than its factorization.

20131320440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384525 (or 384521 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 20131320440 its reverse (4402313102), we get a palindrome (24533633542).

The spelling of 20131320440 in words is "twenty billion, one hundred thirty-one million, three hundred twenty thousand, four hundred forty".