42991061 has 2 divisors, whose sum is σ = 42991062. Its totient is φ = 42991060.

The previous prime is 42991049. The next prime is 42991093. The reversal of 42991061 is 16019924.

It is an a-pointer prime, because the next prime (42991093) can be obtained adding 42991061 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42172036 + 819025 = 6494^2 + 905^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42991061 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42991961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21495530 + 21495531.

It is an arithmetic number, because the mean of its divisors is an integer number (21495531).

Almost surely, 2^42991061 is an apocalyptic number.

It is an amenable number.

42991061 is a deficient number, since it is larger than the sum of its proper divisors (1).

42991061 is an equidigital number, since it uses as much as digits as its factorization.

42991061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 42991061 is about 6556.7568965152. The cubic root of 42991061 is about 350.3155277087.

The spelling of 42991061 in words is "forty-two million, nine hundred ninety-one thousand, sixty-one".