21534684 has 12 divisors (see below), whose sum is σ = 50247624. Its totient is φ = 7178224.

The previous prime is 21534683. The next prime is 21534727. The reversal of 21534684 is 48643512.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21534684² = 927485229959712, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21534683) 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 in 3 ways as a sum of consecutive naturals, for example, 897267 + ... + 897290.

It is an arithmetic number, because the mean of its divisors is an integer number (4187302).

Almost surely, 2^21534684 is an apocalyptic number.

It is an amenable number.

21534684 is an abundant number, since it is smaller than the sum of its proper divisors (28712940).

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

21534684 is a wasteful number, since it uses less digits than its factorization.

21534684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1794564 (or 1794562 counting only the distinct ones).

The product of its digits is 23040, while the sum is 33.

The square root of 21534684 is about 4640.5478124894. The cubic root of 21534684 is about 278.2143336142.

The spelling of 21534684 in words is "twenty-one million, five hundred thirty-four thousand, six hundred eighty-four".