21125480 has 16 divisors (see below), whose sum is σ = 47532420. Its totient is φ = 8450176.

The previous prime is 21125471. The next prime is 21125491. The reversal of 21125480 is 8452112.

It can be written as a sum of positive squares in 2 ways, for example, as 20268004 + 857476 = 4502^2 + 926^2 .

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, 264029 + ... + 264108.

Almost surely, 2^21125480 is an apocalyptic number.

21125480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21125480 is an abundant number, since it is smaller than the sum of its proper divisors (26406940).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21125480 is a wasteful number, since it uses less digits than its factorization.

21125480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528148 (or 528144 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 21125480 is about 4596.2462945321. The cubic root of 21125480 is about 276.4408344053.

Adding to 21125480 its reverse (8452112), we get a palindrome (29577592).

The spelling of 21125480 in words is "twenty-one million, one hundred twenty-five thousand, four hundred eighty".