21413555 has 4 divisors (see below), whose sum is σ = 25696272. Its totient is φ = 17130840.

The previous prime is 21413549. The next prime is 21413569. The reversal of 21413555 is 55531412.

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

It is not a de Polignac number, because 21413555 - 2¹⁴ = 21397171 is a prime.

It is a Duffinian 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, 2141351 + ... + 2141360.

It is an arithmetic number, because the mean of its divisors is an integer number (6424068).

Almost surely, 2^21413555 is an apocalyptic number.

21413555 is a deficient number, since it is larger than the sum of its proper divisors (4282717).

21413555 is an equidigital number, since it uses as much as digits as its factorization.

21413555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4282716.

The product of its digits is 3000, while the sum is 26.

The square root of 21413555 is about 4627.4782549462. The cubic root of 21413555 is about 277.6917161241.

Adding to 21413555 its reverse (55531412), we get a palindrome (76944967).

The spelling of 21413555 in words is "twenty-one million, four hundred thirteen thousand, five hundred fifty-five".