21688674426 has 96 divisors (see below), whose sum is σ = 52191578880. Its totient is φ = 6650125056.

The previous prime is 21688674421. The next prime is 21688674461. The reversal of 21688674426 is 62447688612.

It is a happy number.

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 (21688674421) 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, 30590160 + ... + 30590868.

It is an arithmetic number, because the mean of its divisors is an integer number (543662280).

Almost surely, 2^21688674426 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21688674426, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26095789440).

21688674426 is an abundant number, since it is smaller than the sum of its proper divisors (30502904454).

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

21688674426 is an equidigital number, since it uses as much as digits as its factorization.

21688674426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1493 (or 778 counting only the distinct ones).

The product of its digits is 6193152, while the sum is 54.

The spelling of 21688674426 in words is "twenty-one billion, six hundred eighty-eight million, six hundred seventy-four thousand, four hundred twenty-six".