642257680 has 40 divisors (see below), whose sum is σ = 1501022232. Its totient is φ = 255565824.

The previous prime is 642257677. The next prime is 642257689. The reversal of 642257680 is 86752246.

It can be written as a sum of positive squares in 4 ways, for example, as 6411024 + 635846656 = 2532^2 + 25216^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (642257689) 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, 5359 + ... + 36238.

Almost surely, 2^642257680 is an apocalyptic number.

It is an amenable number.

642257680 is an abundant number, since it is smaller than the sum of its proper divisors (858764552).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642257680 is a wasteful number, since it uses less digits than its factorization.

642257680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41803 (or 41797 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 40.

The square root of 642257680 is about 25342.8033177074. The cubic root of 642257680 is about 862.7860251397.

The spelling of 642257680 in words is "six hundred forty-two million, two hundred fifty-seven thousand, six hundred eighty".