21087084 has 12 divisors (see below), whose sum is σ = 49203224. Its totient is φ = 7029024.

The previous prime is 21087061. The next prime is 21087133. The reversal of 21087084 is 48078012.

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

It is a super-2 number, since 2×21087084² = 889330223246112, which contains 22 as substring.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 878617 + ... + 878640.

Almost surely, 2^21087084 is an apocalyptic number.

It is an amenable number.

21087084 is an abundant number, since it is smaller than the sum of its proper divisors (28116140).

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

21087084 is a wasteful number, since it uses less digits than its factorization.

21087084 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1757264 (or 1757262 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 21087084 is about 4592.0675082146. The cubic root of 21087084 is about 276.2732538454.

The spelling of 21087084 in words is "twenty-one million, eighty-seven thousand, eighty-four".