21101255 has 16 divisors (see below), whose sum is σ = 29040960. Its totient is φ = 14418432.

The previous prime is 21101251. The next prime is 21101257. The reversal of 21101255 is 55210112.

It is not a de Polignac number, because 21101255 - 2² = 21101251 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10901 + ... + 12689.

It is an arithmetic number, because the mean of its divisors is an integer number (1815060).

Almost surely, 2^21101255 is an apocalyptic number.

21101255 is a deficient number, since it is larger than the sum of its proper divisors (7939705).

21101255 is a wasteful number, since it uses less digits than its factorization.

21101255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2138.

The product of its (nonzero) digits is 100, while the sum is 17.

The square root of 21101255 is about 4593.6102359691. The cubic root of 21101255 is about 276.3351272905.

Adding to 21101255 its reverse (55210112), we get a palindrome (76311367).

The spelling of 21101255 in words is "twenty-one million, one hundred one thousand, two hundred fifty-five".