99978559 has 2 divisors, whose sum is σ = 99978560. Its totient is φ = 99978558.

The previous prime is 99978533. The next prime is 99978583. The reversal of 99978559 is 95587999.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 99978559 - 2¹¹ = 99976511 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 99978497 and 99978506.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99978059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49989279 + 49989280.

It is an arithmetic number, because the mean of its divisors is an integer number (49989280).

Almost surely, 2^99978559 is an apocalyptic number.

99978559 is a deficient number, since it is larger than the sum of its proper divisors (1).

99978559 is an equidigital number, since it uses as much as digits as its factorization.

99978559 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9185400, while the sum is 61.

The square root of 99978559 is about 9998.9278925293. The cubic root of 99978559 is about 464.1257075547.

The spelling of 99978559 in words is "ninety-nine million, nine hundred seventy-eight thousand, five hundred fifty-nine".