42723161221 has 16 divisors (see below), whose sum is σ = 48777369088. Its totient is φ = 37133121600.

The previous prime is 42723161167. The next prime is 42723161233. The reversal of 42723161221 is 12216132724.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 42723161221 - 2⁷ = 42723161093 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42723161281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1417695 + ... + 1447516.

It is an arithmetic number, because the mean of its divisors is an integer number (3048585568).

Almost surely, 2^42723161221 is an apocalyptic number.

It is an amenable number.

42723161221 is a deficient number, since it is larger than the sum of its proper divisors (6054207867).

42723161221 is a wasteful number, since it uses less digits than its factorization.

42723161221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2865292.

The product of its digits is 8064, while the sum is 31.

Adding to 42723161221 its reverse (12216132724), we get a palindrome (54939293945).

The spelling of 42723161221 in words is "forty-two billion, seven hundred twenty-three million, one hundred sixty-one thousand, two hundred twenty-one".