55781457789 has 4 divisors (see below), whose sum is σ = 74375277056. Its totient is φ = 37187638524.

The previous prime is 55781457751. The next prime is 55781457799. The reversal of 55781457789 is 98775418755.

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 not a de Polignac number, because 55781457789 - 2⁸ = 55781457533 is a prime.

It is a super-2 number, since 2×55781457789² (a number of 22 digits) 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 (55781457749) 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, 9296909629 + ... + 9296909634.

It is an arithmetic number, because the mean of its divisors is an integer number (18593819264).

Almost surely, 2^55781457789 is an apocalyptic number.

It is an amenable number.

55781457789 is a deficient number, since it is larger than the sum of its proper divisors (18593819267).

55781457789 is a wasteful number, since it uses less digits than its factorization.

55781457789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18593819266.

The product of its digits is 98784000, while the sum is 66.

The spelling of 55781457789 in words is "fifty-five billion, seven hundred eighty-one million, four hundred fifty-seven thousand, seven hundred eighty-nine".