99978051587 has 2 divisors, whose sum is σ = 99978051588. Its totient is φ = 99978051586.

The previous prime is 99978051577. The next prime is 99978051619. The reversal of 99978051587 is 78515087999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 99978051587 - 2²⁰ = 99977003011 is a prime.

It is a super-2 number, since 2×99978051587² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (99978051527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49989025793 + 49989025794.

It is an arithmetic number, because the mean of its divisors is an integer number (49989025794).

Almost surely, 2^99978051587 is an apocalyptic number.

99978051587 is a deficient number, since it is larger than the sum of its proper divisors (1).

99978051587 is an equidigital number, since it uses as much as digits as its factorization.

99978051587 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 57153600, while the sum is 68.

The spelling of 99978051587 in words is "ninety-nine billion, nine hundred seventy-eight million, fifty-one thousand, five hundred eighty-seven".