42640555 has 4 divisors (see below), whose sum is σ = 51168672. Its totient is φ = 34112440.

The previous prime is 42640553. The next prime is 42640561. The reversal of 42640555 is 55504624.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 42640555 - 2¹ = 42640553 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42640553) 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, 4264051 + ... + 4264060.

It is an arithmetic number, because the mean of its divisors is an integer number (12792168).

Almost surely, 2^42640555 is an apocalyptic number.

42640555 is a deficient number, since it is larger than the sum of its proper divisors (8528117).

42640555 is an equidigital number, since it uses as much as digits as its factorization.

42640555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8528116.

The product of its (nonzero) digits is 24000, while the sum is 31.

The square root of 42640555 is about 6529.9735834075. The cubic root of 42640555 is about 349.3608880920.

The spelling of 42640555 in words is "forty-two million, six hundred forty thousand, five hundred fifty-five".