42121997 has 2 divisors, whose sum is σ = 42121998. Its totient is φ = 42121996.

The previous prime is 42121991. The next prime is 42122023. The reversal of 42121997 is 79912124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39363076 + 2758921 = 6274^2 + 1661^2 .

It is a cyclic number.

It is not a de Polignac number, because 42121997 - 2⁸ = 42121741 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 (42121991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21060998 + 21060999.

It is an arithmetic number, because the mean of its divisors is an integer number (21060999).

Almost surely, 2^42121997 is an apocalyptic number.

It is an amenable number.

42121997 is a deficient number, since it is larger than the sum of its proper divisors (1).

42121997 is an equidigital number, since it uses as much as digits as its factorization.

42121997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 35.

The square root of 42121997 is about 6490.1461462744. The cubic root of 42121997 is about 347.9388985296.

The spelling of 42121997 in words is "forty-two million, one hundred twenty-one thousand, nine hundred ninety-seven".