21894924240 has 640 divisors, whose sum is σ = 92256952320. Its totient is φ = 4658798592.

The previous prime is 21894924239. The next prime is 21894924251. The reversal of 21894924240 is 4242949812.

21894924240 is a `hidden beast` number, since 2 + 1 + 89 + 492 + 42 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 26474707 + ... + 26475533.

It is an arithmetic number, because the mean of its divisors is an integer number (144151488).

Almost surely, 2^21894924240 is an apocalyptic number.

21894924240 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 21894924240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46128476160).

21894924240 is an abundant number, since it is smaller than the sum of its proper divisors (70362028080).

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

21894924240 is a wasteful number, since it uses less digits than its factorization.

21894924240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 976 (or 964 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The spelling of 21894924240 in words is "twenty-one billion, eight hundred ninety-four million, nine hundred twenty-four thousand, two hundred forty".