21488140 has 24 divisors (see below), whose sum is σ = 45243072. Its totient is φ = 8572800.

The previous prime is 21488113. The next prime is 21488143. The reversal of 21488140 is 4188412.

It is a junction number, because it is equal to n+sod(n) for n = 21488099 and 21488108.

It is not an unprimeable number, because it can be changed into a prime (21488143) 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 in 7 ways as a sum of consecutive naturals, for example, 7965 + ... + 10315.

It is an arithmetic number, because the mean of its divisors is an integer number (1885128).

Almost surely, 2^21488140 is an apocalyptic number.

21488140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21488140 is an abundant number, since it is smaller than the sum of its proper divisors (23754932).

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

21488140 is a wasteful number, since it uses less digits than its factorization.

21488140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2817 (or 2815 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 28.

The square root of 21488140 is about 4635.5301746402. The cubic root of 21488140 is about 278.0137494709.

The spelling of 21488140 in words is "twenty-one million, four hundred eighty-eight thousand, one hundred forty".