20158997 has 4 divisors (see below), whose sum is σ = 20188140. Its totient is φ = 20129856.

The previous prime is 20158993. The next prime is 20159033. The reversal of 20158997 is 79985102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5058001 + 15100996 = 2249^2 + 3886^2 .

It is a cyclic number.

It is not a de Polignac number, because 20158997 - 2² = 20158993 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20158993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13508 + ... + 14925.

It is an arithmetic number, because the mean of its divisors is an integer number (5047035).

Almost surely, 2^20158997 is an apocalyptic number.

It is an amenable number.

20158997 is a deficient number, since it is larger than the sum of its proper divisors (29143).

20158997 is an equidigital number, since it uses as much as digits as its factorization.

20158997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29142.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 20158997 is about 4489.8771698121. The cubic root of 20158997 is about 272.1591710022.

The spelling of 20158997 in words is "twenty million, one hundred fifty-eight thousand, nine hundred ninety-seven".