21248660 has 24 divisors (see below), whose sum is σ = 45712296. Its totient is φ = 8291840.

The previous prime is 21248659. The next prime is 21248663. The reversal of 21248660 is 6684212.

It can be written as a sum of positive squares in 4 ways, for example, as 198916 + 21049744 = 446^2 + 4588^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21248663) 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, 12137 + ... + 13776.

It is an arithmetic number, because the mean of its divisors is an integer number (1904679).

Almost surely, 2^21248660 is an apocalyptic number.

21248660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21248660 is an abundant number, since it is smaller than the sum of its proper divisors (24463636).

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

21248660 is a wasteful number, since it uses less digits than its factorization.

21248660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25963 (or 25961 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 21248660 is about 4609.6268829483. The cubic root of 21248660 is about 276.9770906431.

The spelling of 21248660 in words is "twenty-one million, two hundred forty-eight thousand, six hundred sixty".