55128783 has 4 divisors (see below), whose sum is σ = 73505048. Its totient is φ = 36752520.

The previous prime is 55128781. The next prime is 55128803. The reversal of 55128783 is 38782155.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 55128783 - 2¹ = 55128781 is a prime.

It is a super-3 number, since 3×55128783³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55128781) 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, 9188128 + ... + 9188133.

It is an arithmetic number, because the mean of its divisors is an integer number (18376262).

Almost surely, 2^55128783 is an apocalyptic number.

55128783 is a deficient number, since it is larger than the sum of its proper divisors (18376265).

55128783 is a wasteful number, since it uses less digits than its factorization.

55128783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18376264.

The product of its digits is 67200, while the sum is 39.

The square root of 55128783 is about 7424.8759585598. The cubic root of 55128783 is about 380.5918362989.

The spelling of 55128783 in words is "fifty-five million, one hundred twenty-eight thousand, seven hundred eighty-three".