642118678 has 4 divisors (see below), whose sum is σ = 963178020. Its totient is φ = 321059338.

The previous prime is 642118657. The next prime is 642118681. The reversal of 642118678 is 876811246.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 876811246 = 2 ⋅438405623.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160529668 + ... + 160529671.

It is an arithmetic number, because the mean of its divisors is an integer number (240794505).

Almost surely, 2^642118678 is an apocalyptic number.

642118678 is a deficient number, since it is larger than the sum of its proper divisors (321059342).

642118678 is a wasteful number, since it uses less digits than its factorization.

642118678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321059341.

The product of its digits is 129024, while the sum is 43.

The square root of 642118678 is about 25340.0607339446. The cubic root of 642118678 is about 862.7237772083.

The spelling of 642118678 in words is "six hundred forty-two million, one hundred eighteen thousand, six hundred seventy-eight".