20991027 has 8 divisors (see below), whose sum is σ = 28073920. Its totient is φ = 13951080.

The previous prime is 20991023. The next prime is 20991043. The reversal of 20991027 is 72019902.

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

It is not a de Polignac number, because 20991027 - 2² = 20991023 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20990985 and 20991003.

It is not an unprimeable number, because it can be changed into a prime (20991023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9577 + ... + 11562.

It is an arithmetic number, because the mean of its divisors is an integer number (3509240).

Almost surely, 2^20991027 is an apocalyptic number.

20991027 is a deficient number, since it is larger than the sum of its proper divisors (7082893).

20991027 is a wasteful number, since it uses less digits than its factorization.

20991027 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21473.

The product of its (nonzero) digits is 2268, while the sum is 30.

The square root of 20991027 is about 4581.5965557871. The cubic root of 20991027 is about 275.8531170771.

The spelling of 20991027 in words is "twenty million, nine hundred ninety-one thousand, twenty-seven".