21361968 has 100 divisors (see below), whose sum is σ = 63196848. Its totient is φ = 6963840.

The previous prime is 21361957. The next prime is 21362041. The reversal of 21361968 is 86916312.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 68533 + ... + 68843.

Almost surely, 2^21361968 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 21361968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31598424).

21361968 is an abundant number, since it is smaller than the sum of its proper divisors (41834880).

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

21361968 is a wasteful number, since it uses less digits than its factorization.

21361968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384 (or 369 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21361968 is about 4621.9009076353. The cubic root of 21361968 is about 277.4685428184.

The spelling of 21361968 in words is "twenty-one million, three hundred sixty-one thousand, nine hundred sixty-eight".