55221817 has 8 divisors (see below), whose sum is σ = 64180800. Its totient is φ = 46530384.

The previous prime is 55221769. The next prime is 55221821. The reversal of 55221817 is 71812255.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55221817 - 2¹⁵ = 55189049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55221877) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66442 + ... + 67267.

It is an arithmetic number, because the mean of its divisors is an integer number (8022600).

Almost surely, 2^55221817 is an apocalyptic number.

It is an amenable number.

55221817 is a deficient number, since it is larger than the sum of its proper divisors (8958983).

55221817 is a wasteful number, since it uses less digits than its factorization.

55221817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133775.

The product of its digits is 5600, while the sum is 31.

The square root of 55221817 is about 7431.1383381014. The cubic root of 55221817 is about 380.8058085032.

The spelling of 55221817 in words is "fifty-five million, two hundred twenty-one thousand, eight hundred seventeen".