42011721 has 6 divisors (see below), whose sum is σ = 60683610. Its totient is φ = 28007808.

The previous prime is 42011707. The next prime is 42011773. The reversal of 42011721 is 12711024.

It can be written as a sum of positive squares in only one way, i.e., 22695696 + 19316025 = 4764^2 + 4395^2 .

It is not a de Polignac number, because 42011721 - 2⁹ = 42011209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 42011694 and 42011703.

It is not an unprimeable number, because it can be changed into a prime (42011701) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2333976 + ... + 2333993.

It is an arithmetic number, because the mean of its divisors is an integer number (10113935).

Almost surely, 2^42011721 is an apocalyptic number.

It is an amenable number.

42011721 is a deficient number, since it is larger than the sum of its proper divisors (18671889).

42011721 is a wasteful number, since it uses less digits than its factorization.

42011721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4667975 (or 4667972 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 42011721 is about 6481.6449301084. The cubic root of 42011721 is about 347.6349968052.

Adding to 42011721 its reverse (12711024), we get a palindrome (54722745).

The spelling of 42011721 in words is "forty-two million, eleven thousand, seven hundred twenty-one".