42597721 has 4 divisors (see below), whose sum is σ = 42613632. Its totient is φ = 42581812.

The previous prime is 42597713. The next prime is 42597727. The reversal of 42597721 is 12779524.

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 42597721 - 2³ = 42597713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42597727) 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, 2845 + ... + 9658.

It is an arithmetic number, because the mean of its divisors is an integer number (10653408).

Almost surely, 2^42597721 is an apocalyptic number.

It is an amenable number.

42597721 is a deficient number, since it is larger than the sum of its proper divisors (15911).

42597721 is a wasteful number, since it uses less digits than its factorization.

42597721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15910.

The product of its digits is 35280, while the sum is 37.

The square root of 42597721 is about 6526.6929604510. The cubic root of 42597721 is about 349.2438669613.

The spelling of 42597721 in words is "forty-two million, five hundred ninety-seven thousand, seven hundred twenty-one".