20118021 has 64 divisors (see below), whose sum is σ = 36495360. Its totient is φ = 9538560.

The previous prime is 20118013. The next prime is 20118029. The reversal of 20118021 is 12081102.

It is an interprime number because it is at equal distance from previous prime (20118013) and next prime (20118029).

It is not a de Polignac number, because 20118021 - 2³ = 20118013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20118029) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 184515 + ... + 184623.

It is an arithmetic number, because the mean of its divisors is an integer number (570240).

Almost surely, 2^20118021 is an apocalyptic number.

20118021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20118021 is a deficient number, since it is larger than the sum of its proper divisors (16377339).

20118021 is a wasteful number, since it uses less digits than its factorization.

20118021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194.

The product of its (nonzero) digits is 32, while the sum is 15.

The square root of 20118021 is about 4485.3116948547. The cubic root of 20118021 is about 271.9746453082.

Adding to 20118021 its reverse (12081102), we get a palindrome (32199123).

The spelling of 20118021 in words is "twenty million, one hundred eighteen thousand, twenty-one".