21541255 has 4 divisors (see below), whose sum is σ = 25849512. Its totient is φ = 17233000.

The previous prime is 21541241. The next prime is 21541259. The reversal of 21541255 is 55214512.

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

It is not a de Polignac number, because 21541255 - 2⁷ = 21541127 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 (21541259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2154121 + ... + 2154130.

It is an arithmetic number, because the mean of its divisors is an integer number (6462378).

Almost surely, 2^21541255 is an apocalyptic number.

21541255 is a deficient number, since it is larger than the sum of its proper divisors (4308257).

21541255 is an equidigital number, since it uses as much as digits as its factorization.

21541255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4308256.

The product of its digits is 2000, while the sum is 25.

The square root of 21541255 is about 4641.2557567969. The cubic root of 21541255 is about 278.2426284411.

Adding to 21541255 its reverse (55214512), we get a palindrome (76755767).

It can be divided in two parts, 21541 and 255, that multiplied together give a triangular number (5492955 = T₃₃₁₄).

The spelling of 21541255 in words is "twenty-one million, five hundred forty-one thousand, two hundred fifty-five".