20784123889 has 3 divisors (see below), whose sum is σ = 20784268057. Its totient is φ = 20783979722.

The previous prime is 20784123851. The next prime is 20784123901. The reversal of 20784123889 is 98832148702.

It is a happy number.

The square root of 20784123889 is 144167.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 20784123889 - 2⁷ = 20784123761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20784123589) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 72084 + ... + 216250.

Almost surely, 2^20784123889 is an apocalyptic number.

20784123889 is the 144167-th square number.

20784123889 is the 72084-th centered octagonal number.

It is an amenable number.

20784123889 is a deficient number, since it is larger than the sum of its proper divisors (144168).

20784123889 is an frugal number, since it uses more digits than its factorization.

20784123889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288334 (or 144167 counting only the distinct ones).

The product of its (nonzero) digits is 1548288, while the sum is 52.

The spelling of 20784123889 in words is "twenty billion, seven hundred eighty-four million, one hundred twenty-three thousand, eight hundred eighty-nine".