21480940 has 24 divisors (see below), whose sum is σ = 48580560. Its totient is φ = 7931328.

The previous prime is 21480931. The next prime is 21480947. The reversal of 21480940 is 4908412.

It is a super-2 number, since 2×21480940² = 922861566567200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21480899 and 21480908.

It is not an unprimeable number, because it can be changed into a prime (21480947) 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, 41050 + ... + 41569.

It is an arithmetic number, because the mean of its divisors is an integer number (2024190).

Almost surely, 2^21480940 is an apocalyptic number.

21480940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21480940 is an abundant number, since it is smaller than the sum of its proper divisors (27099620).

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

21480940 is a wasteful number, since it uses less digits than its factorization.

21480940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82641 (or 82639 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21480940 is about 4634.7534993784. The cubic root of 21480940 is about 277.9826947805.

The spelling of 21480940 in words is "twenty-one million, four hundred eighty thousand, nine hundred forty".