21438707616 has 192 divisors, whose sum is σ = 66384178560. Its totient is φ = 6707957760.

The previous prime is 21438707581. The next prime is 21438707617. The reversal of 21438707616 is 61670783412.

21438707616 is a `hidden beast` number, since 21 + 4 + 3 + 8 + 7 + 0 + 7 + 616 = 666.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21438707617) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6181915 + ... + 6185381.

It is an arithmetic number, because the mean of its divisors is an integer number (345750930).

Almost surely, 2^21438707616 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 21438707616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33192089280).

21438707616 is an abundant number, since it is smaller than the sum of its proper divisors (44945470944).

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

21438707616 is a wasteful number, since it uses less digits than its factorization.

21438707616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3924 (or 3910 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

The spelling of 21438707616 in words is "twenty-one billion, four hundred thirty-eight million, seven hundred seven thousand, six hundred sixteen".