42643261 has 4 divisors (see below), whose sum is σ = 42656832. Its totient is φ = 42629692.

The previous prime is 42643247. The next prime is 42643267. The reversal of 42643261 is 16234624.

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.

It is a cyclic number.

It is not a de Polignac number, because 42643261 - 2¹⁵ = 42610493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42643267) 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, 630 + ... + 9256.

It is an arithmetic number, because the mean of its divisors is an integer number (10664208).

Almost surely, 2^42643261 is an apocalyptic number.

It is an amenable number.

42643261 is a deficient number, since it is larger than the sum of its proper divisors (13571).

42643261 is an equidigital number, since it uses as much as digits as its factorization.

42643261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13570.

The product of its digits is 6912, while the sum is 28.

The square root of 42643261 is about 6530.1807785084. The cubic root of 42643261 is about 349.3682781660.

Adding to 42643261 its reverse (16234624), we get a palindrome (58877885).

The spelling of 42643261 in words is "forty-two million, six hundred forty-three thousand, two hundred sixty-one".