20884578987 has 4 divisors (see below), whose sum is σ = 27846105320. Its totient is φ = 13923052656.

The previous prime is 20884578971. The next prime is 20884578989. The reversal of 20884578987 is 78987548802.

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

It is not a de Polignac number, because 20884578987 - 2⁴ = 20884578971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20884578989) 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, 3480763162 + ... + 3480763167.

It is an arithmetic number, because the mean of its divisors is an integer number (6961526330).

Almost surely, 2^20884578987 is an apocalyptic number.

20884578987 is a deficient number, since it is larger than the sum of its proper divisors (6961526333).

20884578987 is an equidigital number, since it uses as much as digits as its factorization.

20884578987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6961526332.

The product of its (nonzero) digits is 72253440, while the sum is 66.

The spelling of 20884578987 in words is "twenty billion, eight hundred eighty-four million, five hundred seventy-eight thousand, nine hundred eighty-seven".