21887278812 has 384 divisors, whose sum is σ = 70471188480. Its totient is φ = 5741487360.

The previous prime is 21887278811. The next prime is 21887278871.

It is a happy number.

21887278812 is a `hidden beast` number, since 218 + 87 + 278 + 81 + 2 = 666.

21887278812 is nontrivially palindromic in base 10.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21887278811) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 37286383 + ... + 37286969.

It is an arithmetic number, because the mean of its divisors is an integer number (183518720).

Almost surely, 2^21887278812 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 21887278812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35235594240).

21887278812 is an abundant number, since it is smaller than the sum of its proper divisors (48583909668).

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

21887278812 is a wasteful number, since it uses less digits than its factorization.

21887278812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718 (or 710 counting only the distinct ones).

The product of its digits is 1605632, while the sum is 54.

The spelling of 21887278812 in words is "twenty-one billion, eight hundred eighty-seven million, two hundred seventy-eight thousand, eight hundred twelve".