21354564 has 96 divisors (see below), whose sum is σ = 62963712. Its totient is φ = 5517600.

The previous prime is 21354551. The next prime is 21354577. The reversal of 21354564 is 46545312.

It is an interprime number because it is at equal distance from previous prime (21354551) and next prime (21354577).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 111709 + ... + 111899.

It is an arithmetic number, because the mean of its divisors is an integer number (655872).

Almost surely, 2^21354564 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 21354564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31481856).

21354564 is an abundant number, since it is smaller than the sum of its proper divisors (41609148).

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

21354564 is a wasteful number, since it uses less digits than its factorization.

21354564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238 (or 214 counting only the distinct ones).

The product of its digits is 14400, while the sum is 30.

The square root of 21354564 is about 4621.0998690788. The cubic root of 21354564 is about 277.4364825000.

Adding to 21354564 its reverse (46545312), we get a palindrome (67899876).

The spelling of 21354564 in words is "twenty-one million, three hundred fifty-four thousand, five hundred sixty-four".