642501806 has 4 divisors (see below), whose sum is σ = 963752712. Its totient is φ = 321250902.

The previous prime is 642501787. The next prime is 642501817. The reversal of 642501806 is 608105246.

It is a semiprime because it is the product of two primes.

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, 160625450 + ... + 160625453.

It is an arithmetic number, because the mean of its divisors is an integer number (240938178).

Almost surely, 2^642501806 is an apocalyptic number.

642501806 is a deficient number, since it is larger than the sum of its proper divisors (321250906).

642501806 is a wasteful number, since it uses less digits than its factorization.

642501806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321250905.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 642501806 is about 25347.6193359455. The cubic root of 642501806 is about 862.8953280080.

The spelling of 642501806 in words is "six hundred forty-two million, five hundred one thousand, eight hundred six".