21685484 has 6 divisors (see below), whose sum is σ = 37949604. Its totient is φ = 10842740.

The previous prime is 21685483. The next prime is 21685487. The reversal of 21685484 is 48458612.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21685483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2710682 + ... + 2710689.

It is an arithmetic number, because the mean of its divisors is an integer number (6324934).

Almost surely, 2^21685484 is an apocalyptic number.

It is an amenable number.

21685484 is a deficient number, since it is larger than the sum of its proper divisors (16264120).

21685484 is a wasteful number, since it uses less digits than its factorization.

21685484 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5421375 (or 5421373 counting only the distinct ones).

The product of its digits is 61440, while the sum is 38.

The square root of 21685484 is about 4656.7675484181. The cubic root of 21685484 is about 278.8622367708.

The spelling of 21685484 in words is "twenty-one million, six hundred eighty-five thousand, four hundred eighty-four".