998888644431 has 24 divisors (see below), whose sum is σ = 1519048193520. Its totient is φ = 630764827776.

The previous prime is 998888644427. The next prime is 998888644433. The reversal of 998888644431 is 134446888899.

It is not a de Polignac number, because 998888644431 - 2² = 998888644427 is a prime.

It is a super-2 number, since 2×998888644431² (a number of 25 digits) contains 22 as substring.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 998888644431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998888644433) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 449995 + ... + 1483331.

It is an arithmetic number, because the mean of its divisors is an integer number (63293674730).

Almost surely, 2^998888644431 is an apocalyptic number.

998888644431 is a deficient number, since it is larger than the sum of its proper divisors (520159549089).

998888644431 is a wasteful number, since it uses less digits than its factorization.

998888644431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1039015 (or 1039012 counting only the distinct ones).

The product of its digits is 382205952, while the sum is 72.

The spelling of 998888644431 in words is "nine hundred ninety-eight billion, eight hundred eighty-eight million, six hundred forty-four thousand, four hundred thirty-one".