401731991 has 6 divisors (see below), whose sum is σ = 423988992. Its totient is φ = 380587860.

The previous prime is 401731969. The next prime is 401732011. The reversal of 401731991 is 199137104.

It is a happy number.

It is not a de Polignac number, because 401731991 - 2¹⁴ = 401715607 is a prime.

It is a super-2 number, since 2×401731991² = 322777185185648162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (401731901) 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 in 5 ways as a sum of consecutive naturals, for example, 556055 + ... + 556776.

It is an arithmetic number, because the mean of its divisors is an integer number (70664832).

Almost surely, 2^401731991 is an apocalyptic number.

401731991 is a deficient number, since it is larger than the sum of its proper divisors (22257001).

401731991 is a wasteful number, since it uses less digits than its factorization.

401731991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1112869 (or 1112850 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 401731991 is about 20043.2530044402. The cubic root of 401731991 is about 737.8682200692.

The spelling of 401731991 in words is "four hundred one million, seven hundred thirty-one thousand, nine hundred ninety-one".