21055365540 has 288 divisors, whose sum is σ = 72218345472. Its totient is φ = 4919328000.

The previous prime is 21055365517. The next prime is 21055365553. The reversal of 21055365540 is 4556355012.

21055365540 is a `hidden beast` number, since 2 + 1 + 0 + 5 + 53 + 65 + 540 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21055365495 and 21055365504.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 19088629 + ... + 19089731.

It is an arithmetic number, because the mean of its divisors is an integer number (250758144).

Almost surely, 2^21055365540 is an apocalyptic number.

21055365540 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 21055365540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36109172736).

21055365540 is an abundant number, since it is smaller than the sum of its proper divisors (51162979932).

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

21055365540 is a wasteful number, since it uses less digits than its factorization.

21055365540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1471 (or 1466 counting only the distinct ones).

The product of its (nonzero) digits is 90000, while the sum is 36.

The spelling of 21055365540 in words is "twenty-one billion, fifty-five million, three hundred sixty-five thousand, five hundred forty".