21328355 has 16 divisors (see below), whose sum is σ = 27060480. Its totient is φ = 16093152.

The previous prime is 21328339. The next prime is 21328367. The reversal of 21328355 is 55382312.

It is not a de Polignac number, because 21328355 - 2⁴ = 21328339 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 32642 + ... + 33288.

It is an arithmetic number, because the mean of its divisors is an integer number (1691280).

Almost surely, 2^21328355 is an apocalyptic number.

21328355 is a deficient number, since it is larger than the sum of its proper divisors (5732125).

21328355 is a wasteful number, since it uses less digits than its factorization.

21328355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018.

The product of its digits is 7200, while the sum is 29.

The square root of 21328355 is about 4618.2632016809. The cubic root of 21328355 is about 277.3229344147.

The spelling of 21328355 in words is "twenty-one million, three hundred twenty-eight thousand, three hundred fifty-five".