20540639440 has 80 divisors (see below), whose sum is σ = 49898592000. Its totient is φ = 7848743936.

The previous prime is 20540639411. The next prime is 20540639461. The reversal of 20540639440 is 4493604502.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20540639440.

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, 1481661 + ... + 1495459.

It is an arithmetic number, because the mean of its divisors is an integer number (623732400).

Almost surely, 2^20540639440 is an apocalyptic number.

20540639440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20540639440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24949296000).

20540639440 is an abundant number, since it is smaller than the sum of its proper divisors (29357952560).

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

20540639440 is a wasteful number, since it uses less digits than its factorization.

20540639440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14644 (or 14638 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 37.

The spelling of 20540639440 in words is "twenty billion, five hundred forty million, six hundred thirty-nine thousand, four hundred forty".