7812641978 has 16 divisors (see below), whose sum is σ = 12428954496. Its totient is φ = 3675225840.

The previous prime is 7812641933. The next prime is 7812642017. The reversal of 7812641978 is 8791462187.

It is a happy number.

It is a super-2 number, since 2×7812641978² (a number of 21 digits) contains 22 as substring.

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 in 7 ways as a sum of consecutive naturals, for example, 1389326 + ... + 1394937.

It is an arithmetic number, because the mean of its divisors is an integer number (776809656).

Almost surely, 2^7812641978 is an apocalyptic number.

7812641978 is a deficient number, since it is larger than the sum of its proper divisors (4616312518).

7812641978 is a wasteful number, since it uses less digits than its factorization.

7812641978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2784349.

The product of its digits is 1354752, while the sum is 53.

The square root of 7812641978 is about 88389.1507935222. The cubic root of 7812641978 is about 1984.2633349422.

The spelling of 7812641978 in words is "seven billion, eight hundred twelve million, six hundred forty-one thousand, nine hundred seventy-eight".