21652388 has 6 divisors (see below), whose sum is σ = 37891686. Its totient is φ = 10826192.

The previous prime is 21652331. The next prime is 21652391. The reversal of 21652388 is 88325612.

It can be written as a sum of positive squares in only one way, i.e., 12054784 + 9597604 = 3472^2 + 3098^2 .

It is a super-2 number, since 2×21652388² = 937651812205088, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2706545 + ... + 2706552.

It is an arithmetic number, because the mean of its divisors is an integer number (6315281).

Almost surely, 2^21652388 is an apocalyptic number.

It is an amenable number.

21652388 is a deficient number, since it is larger than the sum of its proper divisors (16239298).

21652388 is a wasteful number, since it uses less digits than its factorization.

21652388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5413101 (or 5413099 counting only the distinct ones).

The product of its digits is 23040, while the sum is 35.

The square root of 21652388 is about 4653.2126536405. The cubic root of 21652388 is about 278.7202996770.

The spelling of 21652388 in words is "twenty-one million, six hundred fifty-two thousand, three hundred eighty-eight".