21102254 has 4 divisors (see below), whose sum is σ = 31653384. Its totient is φ = 10551126.

The previous prime is 21102251. The next prime is 21102269. The reversal of 21102254 is 45220112.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5275562 + ... + 5275565.

It is an arithmetic number, because the mean of its divisors is an integer number (7913346).

Almost surely, 2^21102254 is an apocalyptic number.

21102254 is a deficient number, since it is larger than the sum of its proper divisors (10551130).

21102254 is a wasteful number, since it uses less digits than its factorization.

21102254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10551129.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 21102254 is about 4593.7189726843. The cubic root of 21102254 is about 276.3394880806.

Adding to 21102254 its reverse (45220112), we get a palindrome (66322366).

The spelling of 21102254 in words is "twenty-one million, one hundred two thousand, two hundred fifty-four".