21897330 has 96 divisors (see below), whose sum is σ = 65142144. Its totient is φ = 4612608.

The previous prime is 21897313. The next prime is 21897371. The reversal of 21897330 is 3379812.

It is a super-2 number, since 2×21897330² = 958986122257800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21897291 and 21897300.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 35182 + ... + 35798.

It is an arithmetic number, because the mean of its divisors is an integer number (678564).

Almost surely, 2^21897330 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21897330, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32571072).

21897330 is an abundant number, since it is smaller than the sum of its proper divisors (43244814).

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

21897330 is a wasteful number, since it uses less digits than its factorization.

21897330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 660 (or 647 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 33.

The square root of 21897330 is about 4679.4583019833. The cubic root of 21897330 is about 279.7673662972.

The spelling of 21897330 in words is "twenty-one million, eight hundred ninety-seven thousand, three hundred thirty".