7781640478 has 4 divisors (see below), whose sum is σ = 11672460720. Its totient is φ = 3890820238.

The previous prime is 7781640467. The next prime is 7781640487. The reversal of 7781640478 is 8740461877.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1945410118 + ... + 1945410121.

It is an arithmetic number, because the mean of its divisors is an integer number (2918115180).

Almost surely, 2^7781640478 is an apocalyptic number.

7781640478 is a deficient number, since it is larger than the sum of its proper divisors (3890820242).

7781640478 is a wasteful number, since it uses less digits than its factorization.

7781640478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3890820241.

The product of its (nonzero) digits is 2107392, while the sum is 52.

The square root of 7781640478 is about 88213.6071023059. The cubic root of 7781640478 is about 1981.6352574287.

The spelling of 7781640478 in words is "seven billion, seven hundred eighty-one million, six hundred forty thousand, four hundred seventy-eight".