401856691 has 2 divisors, whose sum is σ = 401856692. Its totient is φ = 401856690.

The previous prime is 401856677. The next prime is 401856733. The reversal of 401856691 is 196658104.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 401856691 - 2⁷ = 401856563 is a prime.

It is a super-2 number, since 2×401856691² = 322977600202938962, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (401856641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200928345 + 200928346.

It is an arithmetic number, because the mean of its divisors is an integer number (200928346).

Almost surely, 2^401856691 is an apocalyptic number.

401856691 is a deficient number, since it is larger than the sum of its proper divisors (1).

401856691 is an equidigital number, since it uses as much as digits as its factorization.

401856691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 401856691 is about 20046.3635355642. The cubic root of 401856691 is about 737.9445583995.

The spelling of 401856691 in words is "four hundred one million, eight hundred fifty-six thousand, six hundred ninety-one".