7978730618 has 16 divisors (see below), whose sum is σ = 12383913960. Its totient is φ = 3850828800.

The previous prime is 7978730597. The next prime is 7978730621. The reversal of 7978730618 is 8160378797.

It can be written as a sum of positive squares in 4 ways, for example, as 7261937089 + 716793529 = 85217^2 + 26773^2 .

It is a super-2 number, since 2×7978730618² (a number of 21 digits) contains 22 as substring.

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, 249458 + ... + 279618.

Almost surely, 2^7978730618 is an apocalyptic number.

7978730618 is a deficient number, since it is larger than the sum of its proper divisors (4405183342).

7978730618 is a wasteful number, since it uses less digits than its factorization.

7978730618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34753.

The product of its (nonzero) digits is 3556224, while the sum is 56.

The square root of 7978730618 is about 89323.7405060939. The cubic root of 7978730618 is about 1998.2259783889.

The spelling of 7978730618 in words is "seven billion, nine hundred seventy-eight million, seven hundred thirty thousand, six hundred eighteen".