401991018624 has 96 divisors (see below), whose sum is σ = 1245753463500. Its totient is φ = 123689539584.

The previous prime is 401991018623. The next prime is 401991018701. The reversal of 401991018624 is 426810199104.

It is a happy number.

401991018624 is a `hidden beast` number, since 4 + 0 + 1 + 9 + 9 + 1 + 0 + 18 + 624 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 398201385024 + 3789633600 = 631032^2 + 61560^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×401991018624² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 401991018624.

It is not an unprimeable number, because it can be changed into a prime (401991018623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13406199 + ... + 13436150.

Almost surely, 2^401991018624 is an apocalyptic number.

It is an amenable number.

401991018624 is an abundant number, since it is smaller than the sum of its proper divisors (843762444876).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

401991018624 is a wasteful number, since it uses less digits than its factorization.

401991018624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26842382 (or 26842367 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The spelling of 401991018624 in words is "four hundred one billion, nine hundred ninety-one million, eighteen thousand, six hundred twenty-four".