20531443440 has 80 divisors (see below), whose sum is σ = 64690922016. Its totient is φ = 5385292800.

The previous prime is 20531443423. The next prime is 20531443459. The reversal of 20531443440 is 4434413502.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20531443398 and 20531443407.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 686571 + ... + 715850.

Almost surely, 2^20531443440 is an apocalyptic number.

20531443440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20531443440 is an abundant number, since it is smaller than the sum of its proper divisors (44159478576).

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

20531443440 is a wasteful number, since it uses less digits than its factorization.

20531443440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1402498 (or 1402492 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 30.

Adding to 20531443440 its reverse (4434413502), we get a palindrome (24965856942).

The spelling of 20531443440 in words is "twenty billion, five hundred thirty-one million, four hundred forty-three thousand, four hundred forty".