20144990778 has 16 divisors (see below), whose sum is σ = 43952707296. Its totient is φ = 6104542640.

The previous prime is 20144990771. The next prime is 20144990783. The reversal of 20144990778 is 87709944102.

It is a self number, because there is not a number n which added to its sum of digits gives 20144990778.

It is not an unprimeable number, because it can be changed into a prime (20144990771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 152613501 + ... + 152613632.

It is an arithmetic number, because the mean of its divisors is an integer number (2747044206).

Almost surely, 2^20144990778 is an apocalyptic number.

20144990778 is an abundant number, since it is smaller than the sum of its proper divisors (23807716518).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20144990778 is a wasteful number, since it uses less digits than its factorization.

20144990778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305227149.

The product of its (nonzero) digits is 1016064, while the sum is 51.

The spelling of 20144990778 in words is "twenty billion, one hundred forty-four million, nine hundred ninety thousand, seven hundred seventy-eight".