20271989 has 4 divisors (see below), whose sum is σ = 20574624. Its totient is φ = 19969356.

The previous prime is 20271983. The next prime is 20272009. The reversal of 20271989 is 98917202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20271989 - 2⁸ = 20271733 is a prime.

It is a super-2 number, since 2×20271989² = 821907076032242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20271983) 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, 151217 + ... + 151350.

It is an arithmetic number, because the mean of its divisors is an integer number (5143656).

Almost surely, 2^20271989 is an apocalyptic number.

It is an amenable number.

20271989 is a deficient number, since it is larger than the sum of its proper divisors (302635).

20271989 is an equidigital number, since it uses as much as digits as its factorization.

20271989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302634.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 20271989 is about 4502.4425593227. The cubic root of 20271989 is about 272.6667116675. Note that the first 3 decimals are identical.

The spelling of 20271989 in words is "twenty million, two hundred seventy-one thousand, nine hundred eighty-nine".