21004086 has 16 divisors (see below), whose sum is σ = 43143984. Its totient is φ = 6812064.

The previous prime is 21004073. The next prime is 21004099. The reversal of 21004086 is 68040012.

It is an interprime number because it is at equal distance from previous prime (21004073) and next prime (21004099).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 47085 + ... + 47528.

It is an arithmetic number, because the mean of its divisors is an integer number (2696499).

Almost surely, 2^21004086 is an apocalyptic number.

21004086 is an abundant number, since it is smaller than the sum of its proper divisors (22139898).

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

21004086 is a wasteful number, since it uses less digits than its factorization.

21004086 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94655.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21004086 is about 4583.0214924218. The cubic root of 21004086 is about 275.9103100717.

Adding to 21004086 its reverse (68040012), we get a palindrome (89044098).

The spelling of 21004086 in words is "twenty-one million, four thousand, eighty-six".