55220621 has 4 divisors (see below), whose sum is σ = 55340352. Its totient is φ = 55100892.

The previous prime is 55220617. The next prime is 55220623. The reversal of 55220621 is 12602255.

55220621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 12602255 = 5 ⋅2520451.

It is a cyclic number.

It is not a de Polignac number, because 55220621 - 2² = 55220617 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 (55220623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59171 + ... + 60096.

It is an arithmetic number, because the mean of its divisors is an integer number (13835088).

Almost surely, 2^55220621 is an apocalyptic number.

It is an amenable number.

55220621 is a deficient number, since it is larger than the sum of its proper divisors (119731).

55220621 is a wasteful number, since it uses less digits than its factorization.

55220621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119730.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 55220621 is about 7431.0578654725. The cubic root of 55220621 is about 380.8030593058.

Adding to 55220621 its reverse (12602255), we get a palindrome (67822876).

The spelling of 55220621 in words is "fifty-five million, two hundred twenty thousand, six hundred twenty-one".