21380268 has 72 divisors (see below), whose sum is σ = 62518512. Its totient is φ = 5636736.

The previous prime is 21380267. The next prime is 21380269. The reversal of 21380268 is 86208312.

It is an interprime number because it is at equal distance from previous prime (21380267) and next prime (21380269).

It is not an unprimeable number, because it can be changed into a prime (21380267) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6246 + ... + 9042.

Almost surely, 2^21380268 is an apocalyptic number.

21380268 is a gapful number since it is divisible by the number (28) 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 21380268, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31259256).

21380268 is an abundant number, since it is smaller than the sum of its proper divisors (41138244).

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

21380268 is a wasteful number, since it uses less digits than its factorization.

21380268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2831 (or 2822 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21380268 is about 4623.8801887592. The cubic root of 21380268 is about 277.5477525159.

The spelling of 21380268 in words is "twenty-one million, three hundred eighty thousand, two hundred sixty-eight".