42640217 has 2 divisors, whose sum is σ = 42640218. Its totient is φ = 42640216.

The previous prime is 42640201. The next prime is 42640223. The reversal of 42640217 is 71204624.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24840256 + 17799961 = 4984^2 + 4219^2 .

It is a cyclic number.

It is not a de Polignac number, because 42640217 - 2⁴ = 42640201 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (42640417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21320108 + 21320109.

It is an arithmetic number, because the mean of its divisors is an integer number (21320109).

Almost surely, 2^42640217 is an apocalyptic number.

It is an amenable number.

42640217 is a deficient number, since it is larger than the sum of its proper divisors (1).

42640217 is an equidigital number, since it uses as much as digits as its factorization.

42640217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 42640217 is about 6529.9477027002. The cubic root of 42640217 is about 349.3599649936.

The spelling of 42640217 in words is "forty-two million, six hundred forty thousand, two hundred seventeen".