21856402182 has 8 divisors (see below), whose sum is σ = 43712804376. Its totient is φ = 7285467392.

The previous prime is 21856402181. The next prime is 21856402199. The reversal of 21856402182 is 28120465812.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

21856402182 is an admirable number.

It is a super-2 number, since 2×21856402182² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21856402182.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21856402181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1821366843 + ... + 1821366854.

It is an arithmetic number, because the mean of its divisors is an integer number (5464100547).

Almost surely, 2^21856402182 is an apocalyptic number.

21856402182 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21856402182 is a wasteful number, since it uses less digits than its factorization.

21856402182 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3642733702.

The product of its (nonzero) digits is 61440, while the sum is 39.

Adding to 21856402182 its reverse (28120465812), we get a palindrome (49976867994).

The spelling of 21856402182 in words is "twenty-one billion, eight hundred fifty-six million, four hundred two thousand, one hundred eighty-two".