42721 has 8 divisors (see below), whose sum is σ = 51840. Its totient is φ = 34368.

The previous prime is 42719. The next prime is 42727. The reversal of 42721 is 12724.

42721 = T₅₃ + T₅₄ + ... + T₇₃.

42721 = 9² + 10² + ... + 50².

42721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 42721 - 2¹ = 42719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42695 and 42704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61 + ... + 298.

It is an arithmetic number, because the mean of its divisors is an integer number (6480).

2⁴²⁷²¹ is an apocalyptic number.

It is an amenable number.

42721 is a deficient number, since it is larger than the sum of its proper divisors (9119).

42721 is a wasteful number, since it uses less digits than its factorization.

42721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383.

The product of its digits is 112, while the sum is 16.

The square root of 42721 is about 206.6905900132. The cubic root of 42721 is about 34.9580449661.

The spelling of 42721 in words is "forty-two thousand, seven hundred twenty-one", and thus it is an iban number.