42161231721 has 32 divisors (see below), whose sum is σ = 64888750080. Its totient is φ = 23851282176.

The previous prime is 42161231711. The next prime is 42161231747. The reversal of 42161231721 is 12713216124.

It is not a de Polignac number, because 42161231721 - 2⁶ = 42161231657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (42161231711) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3987640 + ... + 3998198.

It is an arithmetic number, because the mean of its divisors is an integer number (2027773440).

Almost surely, 2^42161231721 is an apocalyptic number.

It is an amenable number.

42161231721 is a deficient number, since it is larger than the sum of its proper divisors (22727518359).

42161231721 is a wasteful number, since it uses less digits than its factorization.

42161231721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12453.

The product of its digits is 4032, while the sum is 30.

Adding to 42161231721 its reverse (12713216124), we get a palindrome (54874447845).

The spelling of 42161231721 in words is "forty-two billion, one hundred sixty-one million, two hundred thirty-one thousand, seven hundred twenty-one".