21080986 has 8 divisors (see below), whose sum is σ = 33481620. Its totient is φ = 9920448.

The previous prime is 21080977. The next prime is 21080987. The reversal of 21080986 is 68908012.

It can be written as a sum of positive squares in 2 ways, for example, as 18619225 + 2461761 = 4315^2 + 1569^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (34), and also a Moran number because the ratio is a prime number: 620029 = 21080986 / (2 + 1 + 0 + 8 + 0 + 9 + 8 + 6).

It is not an unprimeable number, because it can be changed into a prime (21080987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 309981 + ... + 310048.

Almost surely, 2^21080986 is an apocalyptic number.

21080986 is a deficient number, since it is larger than the sum of its proper divisors (12400634).

21080986 is a wasteful number, since it uses less digits than its factorization.

21080986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620048.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 21080986 is about 4591.4034891305. The cubic root of 21080986 is about 276.2466202162.

Adding to 21080986 its reverse (68908012), we get a palindrome (89988998).

The spelling of 21080986 in words is "twenty-one million, eighty thousand, nine hundred eighty-six".