20665005240 has 128 divisors (see below), whose sum is σ = 67836683520. Its totient is φ = 4994457600.

The previous prime is 20665005233. The next prime is 20665005259. The reversal of 20665005240 is 4250056602.

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 = 20665005198 and 20665005207.

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, 413272 + ... + 460568.

It is an arithmetic number, because the mean of its divisors is an integer number (529974090).

Almost surely, 2^20665005240 is an apocalyptic number.

20665005240 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 20665005240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33918341760).

20665005240 is an abundant number, since it is smaller than the sum of its proper divisors (47171678280).

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

20665005240 is a wasteful number, since it uses less digits than its factorization.

20665005240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47653 (or 47649 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

The spelling of 20665005240 in words is "twenty billion, six hundred sixty-five million, five thousand, two hundred forty".