21552505 has 8 divisors (see below), whose sum is σ = 27852552. Its totient is φ = 15915648.

The previous prime is 21552499. The next prime is 21552521. The reversal of 21552505 is 50525512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 281961 + 21270544 = 531^2 + 4612^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21552505 - 2³ = 21552497 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21552505.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165724 + ... + 165853.

It is an arithmetic number, because the mean of its divisors is an integer number (3481569).

Almost surely, 2^21552505 is an apocalyptic number.

It is an amenable number.

21552505 is a deficient number, since it is larger than the sum of its proper divisors (6300047).

21552505 is a wasteful number, since it uses less digits than its factorization.

21552505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 331595.

The product of its (nonzero) digits is 2500, while the sum is 25.

The square root of 21552505 is about 4642.4675550832. The cubic root of 21552505 is about 278.2910577582.

The spelling of 21552505 in words is "twenty-one million, five hundred fifty-two thousand, five hundred five".