56172121 has 2 divisors, whose sum is σ = 56172122. Its totient is φ = 56172120.

The previous prime is 56172119. The next prime is 56172143. The reversal of 56172121 is 12127165.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51912025 + 4260096 = 7205^2 + 2064^2 .

It is a cyclic number.

It is not a de Polignac number, because 56172121 - 2¹ = 56172119 is a prime.

Together with 56172119, it forms a pair of twin primes.

It is equal to p_3348061 and since 56172121 and 3348061 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (56172821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28086060 + 28086061.

It is an arithmetic number, because the mean of its divisors is an integer number (28086061).

Almost surely, 2^56172121 is an apocalyptic number.

It is an amenable number.

56172121 is a deficient number, since it is larger than the sum of its proper divisors (1).

56172121 is an equidigital number, since it uses as much as digits as its factorization.

56172121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 25.

The square root of 56172121 is about 7494.8062683434. The cubic root of 56172121 is about 382.9778066387.

Adding to 56172121 its reverse (12127165), we get a palindrome (68299286).

The spelling of 56172121 in words is "fifty-six million, one hundred seventy-two thousand, one hundred twenty-one".