42155521 has 4 divisors (see below), whose sum is σ = 42590212. Its totient is φ = 41720832.

The previous prime is 42155513. The next prime is 42155551. The reversal of 42155521 is 12555124.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17514225 + 24641296 = 4185^2 + 4964^2 .

It is a cyclic number.

It is not a de Polignac number, because 42155521 - 2³ = 42155513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42155551) 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, 217200 + ... + 217393.

It is an arithmetic number, because the mean of its divisors is an integer number (10647553).

Almost surely, 2^42155521 is an apocalyptic number.

It is an amenable number.

42155521 is a deficient number, since it is larger than the sum of its proper divisors (434691).

42155521 is an equidigital number, since it uses as much as digits as its factorization.

42155521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434690.

The product of its digits is 2000, while the sum is 25.

The square root of 42155521 is about 6492.7283171252. The cubic root of 42155521 is about 348.0311797711.

The spelling of 42155521 in words is "forty-two million, one hundred fifty-five thousand, five hundred twenty-one".