42015661 has 4 divisors (see below), whose sum is σ = 42591292. Its totient is φ = 41440032.

The previous prime is 42015629. The next prime is 42015667. The reversal of 42015661 is 16651024.

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 18541636 + 23474025 = 4306^2 + 4845^2 .

It is a cyclic number.

It is not a de Polignac number, because 42015661 - 2⁵ = 42015629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42015667) 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, 287706 + ... + 287851.

It is an arithmetic number, because the mean of its divisors is an integer number (10647823).

Almost surely, 2^42015661 is an apocalyptic number.

It is an amenable number.

42015661 is a deficient number, since it is larger than the sum of its proper divisors (575631).

42015661 is an equidigital number, since it uses as much as digits as its factorization.

42015661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 575630.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 42015661 is about 6481.9488581753. The cubic root of 42015661 is about 347.6458639239.

Adding to 42015661 its reverse (16651024), we get a palindrome (58666685).

The spelling of 42015661 in words is "forty-two million, fifteen thousand, six hundred sixty-one".