55640240 has 20 divisors (see below), whose sum is σ = 129363744. Its totient is φ = 22256064.

The previous prime is 55640209. The next prime is 55640251. The reversal of 55640240 is 4204655.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 347672 + ... + 347831.

Almost surely, 2^55640240 is an apocalyptic number.

It is an amenable number.

55640240 is an abundant number, since it is smaller than the sum of its proper divisors (73723504).

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

55640240 is a wasteful number, since it uses less digits than its factorization.

55640240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695516 (or 695510 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 26.

The square root of 55640240 is about 7459.2385670389. The cubic root of 55640240 is about 381.7651947359.

Adding to 55640240 its reverse (4204655), we get a palindrome (59844895).

The spelling of 55640240 in words is "fifty-five million, six hundred forty thousand, two hundred forty".