20309640778 has 32 divisors (see below), whose sum is σ = 36657561600. Its totient is φ = 8244087984.

The previous prime is 20309640773. The next prime is 20309640781. The reversal of 20309640778 is 87704690302.

It is not an unprimeable number, because it can be changed into a prime (20309640773) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1866951 + ... + 1877797.

It is an arithmetic number, because the mean of its divisors is an integer number (1145548800).

Almost surely, 2^20309640778 is an apocalyptic number.

20309640778 is a deficient number, since it is larger than the sum of its proper divisors (16347920822).

20309640778 is a wasteful number, since it uses less digits than its factorization.

20309640778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17914.

The product of its (nonzero) digits is 508032, while the sum is 46.

The spelling of 20309640778 in words is "twenty billion, three hundred nine million, six hundred forty thousand, seven hundred seventy-eight".