640878142 has 16 divisors (see below), whose sum is σ = 975309120. Its totient is φ = 315798912.

The previous prime is 640878083. The next prime is 640878143. The reversal of 640878142 is 241878046.

It is a junction number, because it is equal to n+sod(n) for n = 640878095 and 640878104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640878143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49963 + ... + 61465.

It is an arithmetic number, because the mean of its divisors is an integer number (60956820).

Almost surely, 2^640878142 is an apocalyptic number.

640878142 is a deficient number, since it is larger than the sum of its proper divisors (334430978).

640878142 is a wasteful number, since it uses less digits than its factorization.

640878142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11907.

The product of its (nonzero) digits is 86016, while the sum is 40.

The square root of 640878142 is about 25315.5711371480. The cubic root of 640878142 is about 862.1678416287.

The spelling of 640878142 in words is "six hundred forty million, eight hundred seventy-eight thousand, one hundred forty-two".