21180086 has 4 divisors (see below), whose sum is σ = 31770132. Its totient is φ = 10590042.

The previous prime is 21180083. The next prime is 21180101. The reversal of 21180086 is 68008112.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21180083) 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, 5295020 + ... + 5295023.

It is an arithmetic number, because the mean of its divisors is an integer number (7942533).

Almost surely, 2^21180086 is an apocalyptic number.

21180086 is a deficient number, since it is larger than the sum of its proper divisors (10590046).

21180086 is a wasteful number, since it uses less digits than its factorization.

21180086 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10590045.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 21180086 is about 4602.1827430036. The cubic root of 21180086 is about 276.6788146470.

Adding to 21180086 its reverse (68008112), we get a palindrome (89188198).

The spelling of 21180086 in words is "twenty-one million, one hundred eighty thousand, eighty-six".