21518421276 has 192 divisors, whose sum is σ = 56853135360. Its totient is φ = 6279840000.

The previous prime is 21518421271. The next prime is 21518421299. The reversal of 21518421276 is 67212481512.

It is a super-2 number, since 2×21518421276² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21518421271) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 120214555 + ... + 120214733.

It is an arithmetic number, because the mean of its divisors is an integer number (296110080).

Almost surely, 2^21518421276 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 21518421276, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28426567680).

21518421276 is an abundant number, since it is smaller than the sum of its proper divisors (35334714084).

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

21518421276 is a wasteful number, since it uses less digits than its factorization.

21518421276 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496 (or 494 counting only the distinct ones).

The product of its digits is 53760, while the sum is 39.

The spelling of 21518421276 in words is "twenty-one billion, five hundred eighteen million, four hundred twenty-one thousand, two hundred seventy-six".