21599778240 has 336 divisors, whose sum is σ = 77405642496. Its totient is φ = 5522227200.

The previous prime is 21599778217. The next prime is 21599778241. The reversal of 21599778240 is 4287799512.

21599778240 is a `hidden beast` number, since 2 + 1 + 599 + 7 + 7 + 8 + 2 + 40 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21599778241) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10087570 + ... + 10089710.

It is an arithmetic number, because the mean of its divisors is an integer number (230373936).

Almost surely, 2^21599778240 is an apocalyptic number.

21599778240 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 21599778240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38702821248).

21599778240 is an abundant number, since it is smaller than the sum of its proper divisors (55805864256).

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

21599778240 is a wasteful number, since it uses less digits than its factorization.

21599778240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2308 (or 2295 counting only the distinct ones).

The product of its (nonzero) digits is 2540160, while the sum is 54.

The spelling of 21599778240 in words is "twenty-one billion, five hundred ninety-nine million, seven hundred seventy-eight thousand, two hundred forty".