20864878077 has 4 divisors (see below), whose sum is σ = 27819837440. Its totient is φ = 13909918716.

The previous prime is 20864878049. The next prime is 20864878079. The reversal of 20864878077 is 77087846802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20864878077 - 2¹⁹ = 20864353789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20864878079) 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, 3477479677 + ... + 3477479682.

It is an arithmetic number, because the mean of its divisors is an integer number (6954959360).

Almost surely, 2^20864878077 is an apocalyptic number.

It is an amenable number.

20864878077 is a deficient number, since it is larger than the sum of its proper divisors (6954959363).

20864878077 is an equidigital number, since it uses as much as digits as its factorization.

20864878077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6954959362.

The product of its (nonzero) digits is 8429568, while the sum is 57.

The spelling of 20864878077 in words is "twenty billion, eight hundred sixty-four million, eight hundred seventy-eight thousand, seventy-seven".