21352655 has 4 divisors (see below), whose sum is σ = 25623192. Its totient is φ = 17082120.

The previous prime is 21352651. The next prime is 21352687. The reversal of 21352655 is 55625312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21352655 - 2² = 21352651 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21352651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2135261 + ... + 2135270.

It is an arithmetic number, because the mean of its divisors is an integer number (6405798).

Almost surely, 2^21352655 is an apocalyptic number.

21352655 is a deficient number, since it is larger than the sum of its proper divisors (4270537).

21352655 is an equidigital number, since it uses as much as digits as its factorization.

21352655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4270536.

The product of its digits is 9000, while the sum is 29.

The square root of 21352655 is about 4620.8933119041. The cubic root of 21352655 is about 277.4282150710.

Adding to 21352655 its reverse (55625312), we get a palindrome (76977967).

The spelling of 21352655 in words is "twenty-one million, three hundred fifty-two thousand, six hundred fifty-five".