40866821 has 2 divisors, whose sum is σ = 40866822. Its totient is φ = 40866820.

The previous prime is 40866817. The next prime is 40866823. The reversal of 40866821 is 12866804.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40768225 + 98596 = 6385^2 + 314^2 .

It is a cyclic number.

It is not a de Polignac number, because 40866821 - 2² = 40866817 is a prime.

Together with 40866823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40866823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20433410 + 20433411.

It is an arithmetic number, because the mean of its divisors is an integer number (20433411).

Almost surely, 2^40866821 is an apocalyptic number.

It is an amenable number.

40866821 is a deficient number, since it is larger than the sum of its proper divisors (1).

40866821 is an equidigital number, since it uses as much as digits as its factorization.

40866821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 40866821 is about 6392.7162458536. The cubic root of 40866821 is about 344.4479612274.

The spelling of 40866821 in words is "forty million, eight hundred sixty-six thousand, eight hundred twenty-one".