642323561 has 4 divisors (see below), whose sum is σ = 700716624. Its totient is φ = 583930500.

The previous prime is 642323543. The next prime is 642323567. The reversal of 642323561 is 165323246.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 642323561 - 2⁶ = 642323497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (642323567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29196515 + ... + 29196536.

It is an arithmetic number, because the mean of its divisors is an integer number (175179156).

Almost surely, 2^642323561 is an apocalyptic number.

It is an amenable number.

642323561 is a deficient number, since it is larger than the sum of its proper divisors (58393063).

642323561 is a wasteful number, since it uses less digits than its factorization.

642323561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58393062.

The product of its digits is 25920, while the sum is 32.

The square root of 642323561 is about 25344.1030813876. The cubic root of 642323561 is about 862.8155248584.

The spelling of 642323561 in words is "six hundred forty-two million, three hundred twenty-three thousand, five hundred sixty-one".