42721305 has 16 divisors (see below), whose sum is σ = 74568384. Its totient is φ = 20713280.

The previous prime is 42721297. The next prime is 42721307. The reversal of 42721305 is 50312724.

It is not a de Polignac number, because 42721305 - 2³ = 42721297 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (42721307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129294 + ... + 129623.

It is an arithmetic number, because the mean of its divisors is an integer number (4660524).

Almost surely, 2^42721305 is an apocalyptic number.

It is an amenable number.

42721305 is a deficient number, since it is larger than the sum of its proper divisors (31847079).

42721305 is a wasteful number, since it uses less digits than its factorization.

42721305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258936.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 42721305 is about 6536.1536854636. The cubic root of 42721305 is about 349.5812815838.

The spelling of 42721305 in words is "forty-two million, seven hundred twenty-one thousand, three hundred five".