55807621 has 4 divisors (see below), whose sum is σ = 55873152. Its totient is φ = 55742092.

The previous prime is 55807613. The next prime is 55807639. The reversal of 55807621 is 12670855.

55807621 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: 12670855 = 5 ⋅2534171.

It is a cyclic number.

It is not a de Polignac number, because 55807621 - 2³ = 55807613 is a prime.

It is a super-2 number, since 2×55807621² = 6228981123359282, 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 (55807021) 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, 31471 + ... + 33196.

It is an arithmetic number, because the mean of its divisors is an integer number (13968288).

Almost surely, 2^55807621 is an apocalyptic number.

It is an amenable number.

55807621 is a deficient number, since it is larger than the sum of its proper divisors (65531).

55807621 is an equidigital number, since it uses as much as digits as its factorization.

55807621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65530.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 55807621 is about 7470.4498525859. The cubic root of 55807621 is about 382.1476294061.

The spelling of 55807621 in words is "fifty-five million, eight hundred seven thousand, six hundred twenty-one".