7778974640 has 40 divisors (see below), whose sum is σ = 18127396320. Its totient is φ = 3104487936.

The previous prime is 7778974603. The next prime is 7778974667. The reversal of 7778974640 is 464798777.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 7778974640.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75629 + ... + 145868.

It is an arithmetic number, because the mean of its divisors is an integer number (453184908).

Almost surely, 2^7778974640 is an apocalyptic number.

It is an amenable number.

7778974640 is an abundant number, since it is smaller than the sum of its proper divisors (10348421680).

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

7778974640 is a wasteful number, since it uses less digits than its factorization.

7778974640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221949 (or 221943 counting only the distinct ones).

The product of its (nonzero) digits is 16595712, while the sum is 59.

The square root of 7778974640 is about 88198.4956787813. The cubic root of 7778974640 is about 1981.4089417414.

The spelling of 7778974640 in words is "seven billion, seven hundred seventy-eight million, nine hundred seventy-four thousand, six hundred forty".