21028472 has 8 divisors (see below), whose sum is σ = 39428400. Its totient is φ = 10514232.

The previous prime is 21028433. The next prime is 21028477. The reversal of 21028472 is 27482012.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21028477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1314272 + ... + 1314287.

It is an arithmetic number, because the mean of its divisors is an integer number (4928550).

Almost surely, 2^21028472 is an apocalyptic number.

It is an amenable number.

21028472 is a deficient number, since it is larger than the sum of its proper divisors (18399928).

21028472 is a wasteful number, since it uses less digits than its factorization.

21028472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2628565 (or 2628561 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 21028472 is about 4585.6811925820. The cubic root of 21028472 is about 276.0170471862.

It can be divided in two parts, 210 and 28472, that added together give a palindrome (28682).

The spelling of 21028472 in words is "twenty-one million, twenty-eight thousand, four hundred seventy-two".