21864904776 has 192 divisors, whose sum is σ = 72147741120. Its totient is φ = 6115979520.

The previous prime is 21864904753. The next prime is 21864904777. The reversal of 21864904776 is 67740946812.

21864904776 is a `hidden beast` number, since 2 + 1 + 86 + 4 + 90 + 477 + 6 = 666.

It is a super-2 number, since 2×21864904776² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (21864904777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 238666 + ... + 317318.

It is an arithmetic number, because the mean of its divisors is an integer number (375769485).

Almost surely, 2^21864904776 is an apocalyptic number.

21864904776 is a gapful number since it is divisible by the number (26) 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 21864904776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36073870560).

21864904776 is an abundant number, since it is smaller than the sum of its proper divisors (50282836344).

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

21864904776 is a wasteful number, since it uses less digits than its factorization.

21864904776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78698 (or 78682 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 54.

The spelling of 21864904776 in words is "twenty-one billion, eight hundred sixty-four million, nine hundred four thousand, seven hundred seventy-six".