20213989 has 4 divisors (see below), whose sum is σ = 20268556. Its totient is φ = 20159424.

The previous prime is 20213983. The next prime is 20214001. The reversal of 20213989 is 98931202.

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 14250625 + 5963364 = 3775^2 + 2442^2 .

It is a cyclic number.

It is not a de Polignac number, because 20213989 - 2³ = 20213981 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 (20213981) 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, 26724 + ... + 27469.

It is an arithmetic number, because the mean of its divisors is an integer number (5067139).

Almost surely, 2^20213989 is an apocalyptic number.

It is an amenable number.

20213989 is a deficient number, since it is larger than the sum of its proper divisors (54567).

20213989 is an equidigital number, since it uses as much as digits as its factorization.

20213989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54566.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 20213989 is about 4495.9969973300. The cubic root of 20213989 is about 272.4064218706.

The spelling of 20213989 in words is "twenty million, two hundred thirteen thousand, nine hundred eighty-nine".