21305254 has 16 divisors (see below), whose sum is σ = 32970240. Its totient is φ = 10320520.

The previous prime is 21305239. The next prime is 21305257. The reversal of 21305254 is 45250312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21305257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7107 + ... + 9649.

It is an arithmetic number, because the mean of its divisors is an integer number (2060640).

Almost surely, 2^21305254 is an apocalyptic number.

21305254 is a deficient number, since it is larger than the sum of its proper divisors (11664986).

21305254 is a wasteful number, since it uses less digits than its factorization.

21305254 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2675.

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21305254 is about 4615.7614756397. The cubic root of 21305254 is about 277.2227742998. Note that the first 3 decimals are identical.

Adding to 21305254 its reverse (45250312), we get a palindrome (66555566).

The spelling of 21305254 in words is "twenty-one million, three hundred five thousand, two hundred fifty-four".