21051066240 has 512 divisors, whose sum is σ = 78263539200. Its totient is φ = 5341593600.

The previous prime is 21051066209. The next prime is 21051066277. The reversal of 21051066240 is 4266015012.

21051066240 is a `hidden beast` number, since 21 + 0 + 5 + 10 + 6 + 624 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 30464295 + ... + 30464985.

It is an arithmetic number, because the mean of its divisors is an integer number (152858475).

Almost surely, 2^21051066240 is an apocalyptic number.

21051066240 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 21051066240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39131769600).

21051066240 is an abundant number, since it is smaller than the sum of its proper divisors (57212472960).

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

21051066240 is a wasteful number, since it uses less digits than its factorization.

21051066240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803 (or 785 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The spelling of 21051066240 in words is "twenty-one billion, fifty-one million, sixty-six thousand, two hundred forty".