21105272 has 16 divisors (see below), whose sum is σ = 40937400. Its totient is φ = 10188640.

The previous prime is 21105239. The next prime is 21105307. The reversal of 21105272 is 27250112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45254 + ... + 45717.

Almost surely, 2^21105272 is an apocalyptic number.

It is an amenable number.

21105272 is a deficient number, since it is larger than the sum of its proper divisors (19832128).

21105272 is a wasteful number, since it uses less digits than its factorization.

21105272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91006 (or 91002 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21105272 is about 4594.0474529547. The cubic root of 21105272 is about 276.3526612835.

Adding to 21105272 its reverse (27250112), we get a palindrome (48355384).

The spelling of 21105272 in words is "twenty-one million, one hundred five thousand, two hundred seventy-two".