640520042 has 16 divisors (see below), whose sum is σ = 1015061760. Its totient is φ = 302636208.

The previous prime is 640520021. The next prime is 640520053. The reversal of 640520042 is 240025046.

It is a super-3 number, since 3×640520042³ (a number of 27 digits) contains 333 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, 114758 + ... + 120209.

It is an arithmetic number, because the mean of its divisors is an integer number (63441360).

Almost surely, 2^640520042 is an apocalyptic number.

640520042 is a deficient number, since it is larger than the sum of its proper divisors (374541718).

640520042 is a wasteful number, since it uses less digits than its factorization.

640520042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235045.

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 640520042 is about 25308.4974267537. The cubic root of 640520042 is about 862.0072287621.

Adding to 640520042 its reverse (240025046), we get a palindrome (880545088).

The spelling of 640520042 in words is "six hundred forty million, five hundred twenty thousand, forty-two".