55782221 has 4 divisors (see below), whose sum is σ = 60853344. Its totient is φ = 50711100.

The previous prime is 55782193. The next prime is 55782227. The reversal of 55782221 is 12228755.

It is a happy number.

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 de Polignac number, because none of the positive numbers 2^k-55782221 is a prime.

It is a super-2 number, since 2×55782221² = 6223312359385682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55782227) 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, 2535545 + ... + 2535566.

It is an arithmetic number, because the mean of its divisors is an integer number (15213336).

Almost surely, 2^55782221 is an apocalyptic number.

It is an amenable number.

55782221 is a deficient number, since it is larger than the sum of its proper divisors (5071123).

55782221 is a wasteful number, since it uses less digits than its factorization.

55782221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5071122.

The product of its digits is 11200, while the sum is 32.

The square root of 55782221 is about 7468.7496276151. The cubic root of 55782221 is about 382.0896443580.

The spelling of 55782221 in words is "fifty-five million, seven hundred eighty-two thousand, two hundred twenty-one".