642937561 has 32 divisors (see below), whose sum is σ = 819394560. Its totient is φ = 491774976.

The previous prime is 642937549. The next prime is 642937571. The reversal of 642937561 is 165739246.

642937561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 642937561 - 2¹³ = 642929369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642937531) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 203385 + ... + 206521.

It is an arithmetic number, because the mean of its divisors is an integer number (25606080).

Almost surely, 2^642937561 is an apocalyptic number.

It is an amenable number.

642937561 is a deficient number, since it is larger than the sum of its proper divisors (176456999).

642937561 is a wasteful number, since it uses less digits than its factorization.

642937561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3253.

The product of its digits is 272160, while the sum is 43.

The square root of 642937561 is about 25356.2134594265. The cubic root of 642937561 is about 863.0903603937.

The spelling of 642937561 in words is "six hundred forty-two million, nine hundred thirty-seven thousand, five hundred sixty-one".