55538640 has 60 divisors (see below), whose sum is σ = 186519684. Its totient is φ = 14810112.

The previous prime is 55538633. The next prime is 55538657. The reversal of 55538640 is 4683555.

55538640 is a `hidden beast` number, since 5 + 5 + 5 + 3 + 8 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 39087504 + 16451136 = 6252^2 + 4056^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 55538595 and 55538604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37849 + ... + 39288.

Almost surely, 2^55538640 is an apocalyptic number.

It is an amenable number.

55538640 is an abundant number, since it is smaller than the sum of its proper divisors (130981044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55538640 is a wasteful number, since it uses less digits than its factorization.

55538640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77156 (or 77147 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The square root of 55538640 is about 7452.4251086475. The cubic root of 55538640 is about 381.5326832985.

The spelling of 55538640 in words is "fifty-five million, five hundred thirty-eight thousand, six hundred forty".