56172221 has 4 divisors (see below), whose sum is σ = 64196832. Its totient is φ = 48147612.

The previous prime is 56172203. The next prime is 56172223. The reversal of 56172221 is 12227165.

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.

It is a cyclic number.

It is not a de Polignac number, because 56172221 - 2⁶ = 56172157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56172223) 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, 4012295 + ... + 4012308.

It is an arithmetic number, because the mean of its divisors is an integer number (16049208).

Almost surely, 2^56172221 is an apocalyptic number.

It is an amenable number.

56172221 is a deficient number, since it is larger than the sum of its proper divisors (8024611).

56172221 is an equidigital number, since it uses as much as digits as its factorization.

56172221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8024610.

The product of its digits is 1680, while the sum is 26.

The square root of 56172221 is about 7494.8129396270. The cubic root of 56172221 is about 382.9780339030.

Adding to 56172221 its reverse (12227165), we get a palindrome (68399386).

The spelling of 56172221 in words is "fifty-six million, one hundred seventy-two thousand, two hundred twenty-one".