21484240 has 40 divisors (see below), whose sum is σ = 51568128. Its totient is φ = 8315520.

The previous prime is 21484237. The next prime is 21484241. The reversal of 21484240 is 4248412.

It is a tau number, because it is divible by the number of its divisors (40).

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21484241) 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, 1852 + ... + 6811.

Almost surely, 2^21484240 is an apocalyptic number.

21484240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21484240 is an abundant number, since it is smaller than the sum of its proper divisors (30083888).

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

21484240 is a wasteful number, since it uses less digits than its factorization.

21484240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8707 (or 8701 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 25.

The square root of 21484240 is about 4635.1094916949. The cubic root of 21484240 is about 277.9969290415.

The spelling of 21484240 in words is "twenty-one million, four hundred eighty-four thousand, two hundred forty".