55784857 has 4 divisors (see below), whose sum is σ = 55812196. Its totient is φ = 55757520.

The previous prime is 55784851. The next prime is 55784917. The reversal of 55784857 is 75848755.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75848755 = 5 ⋅15169751.

It can be written as a sum of positive squares in 2 ways, for example, as 35390601 + 20394256 = 5949^2 + 4516^2 .

It is a cyclic number.

It is not a de Polignac number, because 55784857 - 2³ = 55784849 is a prime.

It is a super-2 number, since 2×55784857² = 6223900541020898, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55784857.

It is not an unprimeable number, because it can be changed into a prime (55784851) 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, 10338 + ... + 14779.

It is an arithmetic number, because the mean of its divisors is an integer number (13953049).

Almost surely, 2^55784857 is an apocalyptic number.

It is an amenable number.

55784857 is a deficient number, since it is larger than the sum of its proper divisors (27339).

55784857 is a wasteful number, since it uses less digits than its factorization.

55784857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27338.

The product of its digits is 1568000, while the sum is 49.

The square root of 55784857 is about 7468.9260941584. The cubic root of 55784857 is about 382.0956628374.

The spelling of 55784857 in words is "fifty-five million, seven hundred eighty-four thousand, eight hundred fifty-seven".