21540398040 has 960 divisors, whose sum is σ = 91520431200. Its totient is φ = 4514807808.

The previous prime is 21540398039. The next prime is 21540398053. The reversal of 21540398040 is 4089304512.

21540398040 is a `hidden beast` number, since 2 + 1 + 540 + 39 + 80 + 4 + 0 = 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 = 21540397986 and 21540398004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 111608184 + ... + 111608376.

Almost surely, 2^21540398040 is an apocalyptic number.

21540398040 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 21540398040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45760215600).

21540398040 is an abundant number, since it is smaller than the sum of its proper divisors (69980033160).

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

21540398040 is a wasteful number, since it uses less digits than its factorization.

21540398040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286 (or 266 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 21540398040 in words is "twenty-one billion, five hundred forty million, three hundred ninety-eight thousand, forty".