20505012987 has 8 divisors (see below), whose sum is σ = 27803407680. Its totient is φ = 13438313480.

The previous prime is 20505012959. The next prime is 20505012989. The reversal of 20505012987 is 78921050502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20505012987 - 2¹² = 20505008891 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20505012989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57923589 + ... + 57923942.

It is an arithmetic number, because the mean of its divisors is an integer number (3475425960).

Almost surely, 2^20505012987 is an apocalyptic number.

20505012987 is a deficient number, since it is larger than the sum of its proper divisors (7298394693).

20505012987 is a wasteful number, since it uses less digits than its factorization.

20505012987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115847593.

The product of its (nonzero) digits is 50400, while the sum is 39.

The spelling of 20505012987 in words is "twenty billion, five hundred five million, twelve thousand, nine hundred eighty-seven".