20207720987 has 4 divisors (see below), whose sum is σ = 20226949176. Its totient is φ = 20188492800.

The previous prime is 20207720971. The next prime is 20207720999. The reversal of 20207720987 is 78902770202.

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

It is a cyclic number.

It is not a de Polignac number, because 20207720987 - 2⁴ = 20207720971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20207720287) 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, 9612518 + ... + 9614619.

It is an arithmetic number, because the mean of its divisors is an integer number (5056737294).

Almost surely, 2^20207720987 is an apocalyptic number.

20207720987 is a deficient number, since it is larger than the sum of its proper divisors (19228189).

20207720987 is a wasteful number, since it uses less digits than its factorization.

20207720987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19228188.

The product of its (nonzero) digits is 197568, while the sum is 44.

The spelling of 20207720987 in words is "twenty billion, two hundred seven million, seven hundred twenty thousand, nine hundred eighty-seven".