55667781 has 12 divisors (see below), whose sum is σ = 86594508. Its totient is φ = 34257024.

The previous prime is 55667771. The next prime is 55667813. The reversal of 55667781 is 18776655.

55667781 is a `hidden beast` number, since 5 + 566 + 7 + 7 + 81 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2873025 + 52794756 = 1695^2 + 7266^2 .

It is not a de Polignac number, because 55667781 - 2⁵ = 55667749 is a prime.

It is a super-3 number, since 3×55667781³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55667761) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 237780 + ... + 238013.

It is an arithmetic number, because the mean of its divisors is an integer number (7216209).

Almost surely, 2^55667781 is an apocalyptic number.

It is an amenable number.

55667781 is a deficient number, since it is larger than the sum of its proper divisors (30926727).

55667781 is a wasteful number, since it uses less digits than its factorization.

55667781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475812 (or 475809 counting only the distinct ones).

The product of its digits is 352800, while the sum is 45.

The square root of 55667781 is about 7461.0844386054. The cubic root of 55667781 is about 381.8281735017.

The spelling of 55667781 in words is "fifty-five million, six hundred sixty-seven thousand, seven hundred eighty-one".