20727891 has 12 divisors (see below), whose sum is σ = 29979768. Its totient is φ = 13800384.

The previous prime is 20727877. The next prime is 20727901. The reversal of 20727891 is 19872702.

It is not a de Polignac number, because 20727891 - 2⁶ = 20727827 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (20727851) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 12571 + ... + 14123.

It is an arithmetic number, because the mean of its divisors is an integer number (2498314).

Almost surely, 2^20727891 is an apocalyptic number.

20727891 is a deficient number, since it is larger than the sum of its proper divisors (9251877).

20727891 is a wasteful number, since it uses less digits than its factorization.

20727891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3042 (or 3039 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 20727891 is about 4552.7893647741. The cubic root of 20727891 is about 274.6956014765.

The spelling of 20727891 in words is "twenty million, seven hundred twenty-seven thousand, eight hundred ninety-one".