21384655 has 4 divisors (see below), whose sum is σ = 25661592. Its totient is φ = 17107720.

The previous prime is 21384647. The next prime is 21384667. The reversal of 21384655 is 55648312.

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

It is not a de Polignac number, because 21384655 - 2³ = 21384647 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21384655.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2138461 + ... + 2138470.

It is an arithmetic number, because the mean of its divisors is an integer number (6415398).

Almost surely, 2^21384655 is an apocalyptic number.

21384655 is a deficient number, since it is larger than the sum of its proper divisors (4276937).

21384655 is an equidigital number, since it uses as much as digits as its factorization.

21384655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4276936.

The product of its digits is 28800, while the sum is 34.

The square root of 21384655 is about 4624.3545495561. The cubic root of 21384655 is about 277.5667344844.

The spelling of 21384655 in words is "twenty-one million, three hundred eighty-four thousand, six hundred fifty-five".