21426116640 has 96 divisors (see below), whose sum is σ = 67565715840. Its totient is φ = 5707413504.

The previous prime is 21426116567. The next prime is 21426116641. The reversal of 21426116640 is 4661162412.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (21426116641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 425941 + ... + 473579.

It is an arithmetic number, because the mean of its divisors is an integer number (703809540).

Almost surely, 2^21426116640 is an apocalyptic number.

21426116640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21426116640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33782857920).

21426116640 is an abundant number, since it is smaller than the sum of its proper divisors (46139599200).

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

21426116640 is a wasteful number, since it uses less digits than its factorization.

21426116640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48594 (or 48586 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The spelling of 21426116640 in words is "twenty-one billion, four hundred twenty-six million, one hundred sixteen thousand, six hundred forty".