401666831 has 2 divisors, whose sum is σ = 401666832. Its totient is φ = 401666830.

The previous prime is 401666819. The next prime is 401666833. The reversal of 401666831 is 138666104.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 401666831 - 2⁶ = 401666767 is a prime.

It is a super-2 number, since 2×401666831² = 322672486251165122, which contains 22 as substring.

Together with 401666833, 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 = 401666791 and 401666800.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401666833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200833415 + 200833416.

It is an arithmetic number, because the mean of its divisors is an integer number (200833416).

Almost surely, 2^401666831 is an apocalyptic number.

401666831 is a deficient number, since it is larger than the sum of its proper divisors (1).

401666831 is an equidigital number, since it uses as much as digits as its factorization.

401666831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 401666831 is about 20041.6274538771. The cubic root of 401666831 is about 737.8283244057.

The spelling of 401666831 in words is "four hundred one million, six hundred sixty-six thousand, eight hundred thirty-one".