9999998557 has 2 divisors, whose sum is σ = 9999998558. Its totient is φ = 9999998556.

The previous prime is 9999998549. The next prime is 9999998597. The reversal of 9999998557 is 7558999999.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9986204761 + 13793796 = 99931^2 + 3714^2 .

It is a cyclic number.

It is not a de Polignac number, because 9999998557 - 2³ = 9999998549 is a prime.

It is a super-2 number, since 2×9999998557² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9999998597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4999999278 + 4999999279.

It is an arithmetic number, because the mean of its divisors is an integer number (4999999279).

Almost surely, 2^9999998557 is an apocalyptic number.

It is an amenable number.

9999998557 is a deficient number, since it is larger than the sum of its proper divisors (1).

9999998557 is an equidigital number, since it uses as much as digits as its factorization.

9999998557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 744017400, while the sum is 79.

The square root of 9999998557 is about 99999.9927849997. The cubic root of 9999998557 is about 2154.4345864036.

The spelling of 9999998557 in words is "nine billion, nine hundred ninety-nine million, nine hundred ninety-eight thousand, five hundred fifty-seven".