40405217 has 2 divisors, whose sum is σ = 40405218.
Its totient is φ = 40405216.
The previous prime is 40405187. The next prime is 40405219. The reversal of 40405217 is 71250404.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 36012001 + 4393216 = 6001^2 + 2096^2
It is a cyclic number.
It is not a de Polignac number, because 40405217 - 28 = 40404961 is a prime.
Together with 40405219, it forms a pair of twin primes.
It is a Chen prime.
It is a junction number, because it is equal to n+sod(n) for n = 40405192 and 40405201.
It is not a weakly prime, because it can be changed into another prime (40405219) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20202608 + 20202609.
It is an arithmetic number, because the mean of its divisors is an integer number (20202609).
Almost surely, 240405217 is an apocalyptic number.
It is an amenable number.
40405217 is a deficient number, since it is larger than the sum of its proper divisors (1).
40405217 is an equidigital number, since it uses as much as digits as its factorization.
40405217 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 1120, while the sum is 23.
The square root of 40405217 is about 6356.5098127825.
The cubic root of 40405217 is about 343.1461636266.
The spelling of 40405217 in words is "forty million, four hundred five thousand, two hundred seventeen".