21669264 has 60 divisors (see below), whose sum is σ = 62747100. Its totient is φ = 6972672.

The previous prime is 21669259. The next prime is 21669269. The reversal of 21669264 is 46296612.

It is an interprime number because it is at equal distance from previous prime (21669259) and next prime (21669269).

It can be written as a sum of positive squares in 2 ways, for example, as 14379264 + 7290000 = 3792^2 + 2700^2 .

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 not an unprimeable number, because it can be changed into a prime (21669269) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1582 + ... + 6770.

It is an arithmetic number, because the mean of its divisors is an integer number (1045785).

Almost surely, 2^21669264 is an apocalyptic number.

21669264 is a gapful number since it is divisible by the number (24) 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 21669264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31373550).

21669264 is an abundant number, since it is smaller than the sum of its proper divisors (41077836).

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

21669264 is a wasteful number, since it uses less digits than its factorization.

21669264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5232 (or 5223 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21669264 is about 4655.0256712504. The cubic root of 21669264 is about 278.7926929588.

The spelling of 21669264 in words is "twenty-one million, six hundred sixty-nine thousand, two hundred sixty-four".