55720121609 has 4 divisors (see below), whose sum is σ = 58142735616. Its totient is φ = 53297507604.

The previous prime is 55720121603. The next prime is 55720121623. The reversal of 55720121609 is 90612102755.

It is a happy number.

55720121609 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.

It is a cyclic number.

It is not a de Polignac number, because 55720121609 - 2²⁸ = 55451686153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55720121603) 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, 1211306969 + ... + 1211307014.

It is an arithmetic number, because the mean of its divisors is an integer number (14535683904).

Almost surely, 2^55720121609 is an apocalyptic number.

It is an amenable number.

55720121609 is a deficient number, since it is larger than the sum of its proper divisors (2422614007).

55720121609 is a wasteful number, since it uses less digits than its factorization.

55720121609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2422614006.

The product of its (nonzero) digits is 37800, while the sum is 38.

The spelling of 55720121609 in words is "fifty-five billion, seven hundred twenty million, one hundred twenty-one thousand, six hundred nine".