642233561 has 4 divisors (see below), whose sum is σ = 642285072. Its totient is φ = 642182052.

The previous prime is 642233503. The next prime is 642233567. The reversal of 642233561 is 165332246.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 165332246 = 2 ⋅82666123.

It is a cyclic number.

It is not a de Polignac number, because 642233561 - 2¹⁰ = 642232537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642233567) 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, 5990 + ... + 36336.

It is an arithmetic number, because the mean of its divisors is an integer number (160571268).

Almost surely, 2^642233561 is an apocalyptic number.

It is an amenable number.

642233561 is a deficient number, since it is larger than the sum of its proper divisors (51511).

642233561 is a wasteful number, since it uses less digits than its factorization.

642233561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51510.

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

The square root of 642233561 is about 25342.3274582269. The cubic root of 642233561 is about 862.7752248035.

The spelling of 642233561 in words is "six hundred forty-two million, two hundred thirty-three thousand, five hundred sixty-one".