42180661 has 2 divisors, whose sum is σ = 42180662. Its totient is φ = 42180660.

The previous prime is 42180659. The next prime is 42180679. The reversal of 42180661 is 16608124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31979025 + 10201636 = 5655^2 + 3194^2 .

It is a cyclic number.

It is not a de Polignac number, because 42180661 - 2¹ = 42180659 is a prime.

Together with 42180659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42180601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21090330 + 21090331.

It is an arithmetic number, because the mean of its divisors is an integer number (21090331).

Almost surely, 2^42180661 is an apocalyptic number.

It is an amenable number.

42180661 is a deficient number, since it is larger than the sum of its proper divisors (1).

42180661 is an equidigital number, since it uses as much as digits as its factorization.

42180661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 42180661 is about 6494.6640405798. The cubic root of 42180661 is about 348.1003503482.

Adding to 42180661 its reverse (16608124), we get a palindrome (58788785).

The spelling of 42180661 in words is "forty-two million, one hundred eighty thousand, six hundred sixty-one".