55725221 has 4 divisors (see below), whose sum is σ = 56910912. Its totient is φ = 54539532.

The previous prime is 55725217. The next prime is 55725223. The reversal of 55725221 is 12252755.

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: 12252755 = 5 ⋅2450551.

It is a cyclic number.

It is not a de Polignac number, because 55725221 - 2² = 55725217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55725223) 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, 592775 + ... + 592868.

It is an arithmetic number, because the mean of its divisors is an integer number (14227728).

Almost surely, 2^55725221 is an apocalyptic number.

It is an amenable number.

55725221 is a deficient number, since it is larger than the sum of its proper divisors (1185691).

55725221 is a wasteful number, since it uses less digits than its factorization.

55725221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1185690.

The product of its digits is 7000, while the sum is 29.

The square root of 55725221 is about 7464.9327525437. The cubic root of 55725221 is about 381.9594563295.

Adding to 55725221 its reverse (12252755), we get a palindrome (67977976).

The spelling of 55725221 in words is "fifty-five million, seven hundred twenty-five thousand, two hundred twenty-one".