21858681600 has 864 divisors, whose sum is σ = 97083786240. Its totient is φ = 4697948160.

The previous prime is 21858681497. The next prime is 21858681643. The reversal of 21858681600 is 618685812.

21858681600 is a `hidden beast` number, since 2 + 1 + 8 + 586 + 8 + 1 + 60 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a super-2 number, since 2×21858681600² (a number of 21 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 20562669 + ... + 20563731.

Almost surely, 2^21858681600 is an apocalyptic number.

21858681600 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 21858681600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48541893120).

21858681600 is an abundant number, since it is smaller than the sum of its proper divisors (75225104640).

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

21858681600 is a wasteful number, since it uses less digits than its factorization.

21858681600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1122 (or 1097 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The spelling of 21858681600 in words is "twenty-one billion, eight hundred fifty-eight million, six hundred eighty-one thousand, six hundred".