55028781 has 8 divisors (see below), whose sum is σ = 81524160. Its totient is φ = 36685836.

The previous prime is 55028767. The next prime is 55028791. The reversal of 55028781 is 18782055.

55028781 is a `hidden beast` number, since 550 + 28 + 7 + 81 = 666.

It is not a de Polignac number, because 55028781 - 2⁵ = 55028749 is a prime.

It is a super-2 number, since 2×55028781² = 6056333476691922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55028761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1019025 + ... + 1019078.

It is an arithmetic number, because the mean of its divisors is an integer number (10190520).

Almost surely, 2^55028781 is an apocalyptic number.

It is an amenable number.

55028781 is a deficient number, since it is larger than the sum of its proper divisors (26495379).

55028781 is a wasteful number, since it uses less digits than its factorization.

55028781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2038112 (or 2038106 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The square root of 55028781 is about 7418.1386479359. The cubic root of 55028781 is about 380.3615695237.

The spelling of 55028781 in words is "fifty-five million, twenty-eight thousand, seven hundred eighty-one".