20786288491 has 4 divisors (see below), whose sum is σ = 20795459832. Its totient is φ = 20777117152.

The previous prime is 20786288461. The next prime is 20786288503. The reversal of 20786288491 is 19488268702.

It is a happy number.

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 20786288491 - 2¹³ = 20786280299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20786288441) 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, 4582270 + ... + 4586803.

It is an arithmetic number, because the mean of its divisors is an integer number (5198864958).

Almost surely, 2^20786288491 is an apocalyptic number.

20786288491 is a deficient number, since it is larger than the sum of its proper divisors (9171341).

20786288491 is an equidigital number, since it uses as much as digits as its factorization.

20786288491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9171340.

The product of its (nonzero) digits is 3096576, while the sum is 55.

The spelling of 20786288491 in words is "twenty billion, seven hundred eighty-six million, two hundred eighty-eight thousand, four hundred ninety-one".