21478528 has 16 divisors (see below), whose sum is σ = 42789510. Its totient is φ = 10739200.

The previous prime is 21478519. The next prime is 21478529. The reversal of 21478528 is 82587412.

It can be written as a sum of positive squares in only one way, i.e., 21455424 + 23104 = 4632^2 + 152^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a super-2 number, since 2×21478528² = 922654330093568, which contains 22 as substring.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21478529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83773 + ... + 84028.

Almost surely, 2^21478528 is an apocalyptic number.

It is an amenable number.

21478528 is a deficient number, since it is larger than the sum of its proper divisors (21310982).

21478528 is an equidigital number, since it uses as much as digits as its factorization.

21478528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167815 (or 167803 counting only the distinct ones).

The product of its digits is 35840, while the sum is 37.

The square root of 21478528 is about 4634.4932840603. The cubic root of 21478528 is about 277.9722899075.

The spelling of 21478528 in words is "twenty-one million, four hundred seventy-eight thousand, five hundred twenty-eight".