42721513 has 4 divisors (see below), whose sum is σ = 43201620. Its totient is φ = 42241408.

The previous prime is 42721507. The next prime is 42721517. The reversal of 42721513 is 31512724.

It is a happy number.

42721513 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4380649 + 38340864 = 2093^2 + 6192^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42721513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42721517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 239920 + ... + 240097.

It is an arithmetic number, because the mean of its divisors is an integer number (10800405).

Almost surely, 2^42721513 is an apocalyptic number.

It is an amenable number.

42721513 is a deficient number, since it is larger than the sum of its proper divisors (480107).

42721513 is an equidigital number, since it uses as much as digits as its factorization.

42721513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 480106.

The product of its digits is 1680, while the sum is 25.

The square root of 42721513 is about 6536.1695969428. The cubic root of 42721513 is about 349.5818489259.

It can be divided in two parts, 42721 and 513, that added together give a palindrome (43234).

The spelling of 42721513 in words is "forty-two million, seven hundred twenty-one thousand, five hundred thirteen".