21042254 has 8 divisors (see below), whose sum is σ = 31609440. Its totient is φ = 10505776.

The previous prime is 21042251. The next prime is 21042283. The reversal of 21042254 is 45224012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5879 + ... + 8754.

It is an arithmetic number, because the mean of its divisors is an integer number (3951180).

Almost surely, 2^21042254 is an apocalyptic number.

21042254 is a deficient number, since it is larger than the sum of its proper divisors (10567186).

21042254 is a wasteful number, since it uses less digits than its factorization.

21042254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15354.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 21042254 is about 4587.1836675677. The cubic root of 21042254 is about 276.0773342768.

Adding to 21042254 its reverse (45224012), we get a palindrome (66266266).

The spelling of 21042254 in words is "twenty-one million, forty-two thousand, two hundred fifty-four".