20591091 has 12 divisors (see below), whose sum is σ = 30844632. Its totient is φ = 13727232.

The previous prime is 20591071. The next prime is 20591093. The reversal of 20591091 is 19019502.

It is a happy number.

It is not a de Polignac number, because 20591091 - 2⁹ = 20590579 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20591093) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42126 + ... + 42611.

It is an arithmetic number, because the mean of its divisors is an integer number (2570386).

Almost surely, 2^20591091 is an apocalyptic number.

20591091 is a deficient number, since it is larger than the sum of its proper divisors (10253541).

20591091 is an frugal number, since it uses more digits than its factorization.

20591091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84752 (or 84740 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 20591091 is about 4537.7407374155. The cubic root of 20591091 is about 274.0899548358.

The spelling of 20591091 in words is "twenty million, five hundred ninety-one thousand, ninety-one".