55221009 has 4 divisors (see below), whose sum is σ = 73628016. Its totient is φ = 36814004.

The previous prime is 55221007. The next prime is 55221037. The reversal of 55221009 is 90012255.

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 55221009 - 2¹ = 55221007 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 55221009.

It is not an unprimeable number, because it can be changed into a prime (55221007) 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, 9203499 + ... + 9203504.

It is an arithmetic number, because the mean of its divisors is an integer number (18407004).

Almost surely, 2^55221009 is an apocalyptic number.

It is an amenable number.

55221009 is a deficient number, since it is larger than the sum of its proper divisors (18407007).

55221009 is a wasteful number, since it uses less digits than its factorization.

55221009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18407006.

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 55221009 is about 7431.0839720730. The cubic root of 55221009 is about 380.8039511902.

The spelling of 55221009 in words is "fifty-five million, two hundred twenty-one thousand, nine".