642656205 has 12 divisors (see below), whose sum is σ = 1113937500. Its totient is φ = 342749952.

The previous prime is 642656197. The next prime is 642656227. The reversal of 642656205 is 502656246.

642656205 is a `hidden beast` number, since 6 + 4 + 26 + 5 + 620 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 343954116 + 298702089 = 18546^2 + 17283^2 .

It is not a de Polignac number, because 642656205 - 2³ = 642656197 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 642656205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7140580 + ... + 7140669.

It is an arithmetic number, because the mean of its divisors is an integer number (92828125).

Almost surely, 2^642656205 is an apocalyptic number.

It is an amenable number.

642656205 is a deficient number, since it is larger than the sum of its proper divisors (471281295).

642656205 is a wasteful number, since it uses less digits than its factorization.

642656205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14281260 (or 14281257 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 642656205 is about 25350.6647841827. The cubic root of 642656205 is about 862.9644429914.

The spelling of 642656205 in words is "six hundred forty-two million, six hundred fifty-six thousand, two hundred five".