21861047376 has 300 divisors, whose sum is σ = 72780702228. Its totient is φ = 6123027456.

The previous prime is 21861047353. The next prime is 21861047399. The reversal of 21861047376 is 67374016812.

21861047376 is a `hidden beast` number, since 21 + 8 + 610 + 4 + 7 + 3 + 7 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (21861047353) and next prime (21861047399).

It can be written as a sum of positive squares in 2 ways, for example, as 13554547776 + 8306499600 = 116424^2 + 91140^2 .

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 59 ways as a sum of consecutive naturals, for example, 18323836 + ... + 18325028.

Almost surely, 2^21861047376 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21861047376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36390351114).

21861047376 is an abundant number, since it is smaller than the sum of its proper divisors (50919654852).

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

21861047376 is a wasteful number, since it uses less digits than its factorization.

21861047376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1288 (or 1258 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

The spelling of 21861047376 in words is "twenty-one billion, eight hundred sixty-one million, forty-seven thousand, three hundred seventy-six".