55077781 has 4 divisors (see below), whose sum is σ = 60084864. Its totient is φ = 50070700.

The previous prime is 55077779. The next prime is 55077787. The reversal of 55077781 is 18777055.

It is a happy number.

55077781 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 55077781 - 2¹ = 55077779 is a prime.

It is a super-2 number, since 2×55077781² = 6067123919767922, which 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 (55077787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2503525 + ... + 2503546.

It is an arithmetic number, because the mean of its divisors is an integer number (15021216).

Almost surely, 2^55077781 is an apocalyptic number.

It is an amenable number.

55077781 is a deficient number, since it is larger than the sum of its proper divisors (5007083).

55077781 is a wasteful number, since it uses less digits than its factorization.

55077781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5007082.

The product of its (nonzero) digits is 68600, while the sum is 40.

The square root of 55077781 is about 7421.4406283416. The cubic root of 55077781 is about 380.4744328130.

The spelling of 55077781 in words is "fifty-five million, seventy-seven thousand, seven hundred eighty-one".