998555531 has 2 divisors, whose sum is σ = 998555532. Its totient is φ = 998555530.

The previous prime is 998555513. The next prime is 998555549. The reversal of 998555531 is 135555899.

Together with previous prime (998555513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a balanced prime because it is at equal distance from previous prime (998555513) and next prime (998555549).

It is a cyclic number.

It is not a de Polignac number, because 998555531 - 2¹⁰ = 998554507 is a prime.

It is a super-2 number, since 2×998555531² = 1994226296981383922, which 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 998555531.

It is not a weakly prime, because it can be changed into another prime (998555581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499277765 + 499277766.

It is an arithmetic number, because the mean of its divisors is an integer number (499277766).

Almost surely, 2^998555531 is an apocalyptic number.

998555531 is a deficient number, since it is larger than the sum of its proper divisors (1).

998555531 is an equidigital number, since it uses as much as digits as its factorization.

998555531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1215000, while the sum is 50.

The square root of 998555531 is about 31599.9292878956. The cubic root of 998555531 is about 999.5182783148.

The spelling of 998555531 in words is "nine hundred ninety-eight million, five hundred fifty-five thousand, five hundred thirty-one".