20420091 has 12 divisors (see below), whose sum is σ = 30215640. Its totient is φ = 13281120.

The previous prime is 20420083. The next prime is 20420107. The reversal of 20420091 is 19002402.

It is not a de Polignac number, because 20420091 - 2³ = 20420083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20420011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27301 + ... + 28038.

It is an arithmetic number, because the mean of its divisors is an integer number (2517970).

Almost surely, 2^20420091 is an apocalyptic number.

20420091 is a deficient number, since it is larger than the sum of its proper divisors (9795549).

20420091 is a wasteful number, since it uses less digits than its factorization.

20420091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55386 (or 55383 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 20420091 is about 4518.8594800016. The cubic root of 20420091 is about 273.3291124009.

Adding to 20420091 its reverse (19002402), we get a palindrome (39422493).

The spelling of 20420091 in words is "twenty million, four hundred twenty thousand, ninety-one".