72106121 has 4 divisors (see below), whose sum is σ = 75901200. Its totient is φ = 68311044.

The previous prime is 72106079. The next prime is 72106169. The reversal of 72106121 is 12160127.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12160127 = 7 ⋅1737161.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72106121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 72106093 and 72106102.

It is not an unprimeable number, because it can be changed into a prime (72106171) 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, 1897511 + ... + 1897548.

It is an arithmetic number, because the mean of its divisors is an integer number (18975300).

Almost surely, 2^72106121 is an apocalyptic number.

It is an amenable number.

72106121 is a deficient number, since it is larger than the sum of its proper divisors (3795079).

72106121 is a wasteful number, since it uses less digits than its factorization.

72106121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3795078.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 72106121 is about 8491.5323116620. The cubic root of 72106121 is about 416.2210536975.

Adding to 72106121 its reverse (12160127), we get a palindrome (84266248).

It can be divided in two parts, 72106 and 121, that added together give a palindrome (72227).

The spelling of 72106121 in words is "seventy-two million, one hundred six thousand, one hundred twenty-one".