42161661 has 16 divisors (see below), whose sum is σ = 63320320. Its totient is φ = 27721440.

The previous prime is 42161641. The next prime is 42161681. The reversal of 42161661 is 16616124.

42161661 is a `hidden beast` number, since 42 + 1 + 616 + 6 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (42161641) and next prime (42161681).

It is not a de Polignac number, because 42161661 - 2¹⁰ = 42160637 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42161641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8725 + ... + 12666.

It is an arithmetic number, because the mean of its divisors is an integer number (3957520).

Almost surely, 2^42161661 is an apocalyptic number.

It is an amenable number.

42161661 is a deficient number, since it is larger than the sum of its proper divisors (21158659).

42161661 is a wasteful number, since it uses less digits than its factorization.

42161661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21473 (or 21467 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 42161661 is about 6493.2011365735. The cubic root of 42161661 is about 348.0480759977.

Adding to 42161661 its reverse (16616124), we get a palindrome (58777785).

The spelling of 42161661 in words is "forty-two million, one hundred sixty-one thousand, six hundred sixty-one".