2563921678 has 4 divisors (see below), whose sum is σ = 3845882520. Its totient is φ = 1281960838.

The previous prime is 2563921673. The next prime is 2563921699. The reversal of 2563921678 is 8761293652.

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

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2563921673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640980418 + ... + 640980421.

It is an arithmetic number, because the mean of its divisors is an integer number (961470630).

Almost surely, 2^2563921678 is an apocalyptic number.

2563921678 is a deficient number, since it is larger than the sum of its proper divisors (1281960842).

2563921678 is a wasteful number, since it uses less digits than its factorization.

2563921678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1281960841.

The product of its digits is 1088640, while the sum is 49.

The square root of 2563921678 is about 50635.1822155307. The cubic root of 2563921678 is about 1368.6789400138.

The spelling of 2563921678 in words is "two billion, five hundred sixty-three million, nine hundred twenty-one thousand, six hundred seventy-eight".