99987961 has 2 divisors, whose sum is σ = 99987962. Its totient is φ = 99987960.

The previous prime is 99987959. The next prime is 99987973. The reversal of 99987961 is 16978999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72999936 + 26988025 = 8544^2 + 5195^2 .

It is an emirp because it is prime and its reverse (16978999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99987961 - 2¹ = 99987959 is a prime.

Together with 99987959, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 99987896 and 99987905.

It is not a weakly prime, because it can be changed into another prime (99987991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49993980 + 49993981.

It is an arithmetic number, because the mean of its divisors is an integer number (49993981).

Almost surely, 2^99987961 is an apocalyptic number.

It is an amenable number.

99987961 is a deficient number, since it is larger than the sum of its proper divisors (1).

99987961 is an equidigital number, since it uses as much as digits as its factorization.

99987961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2204496, while the sum is 58.

The square root of 99987961 is about 9999.3980318817. The cubic root of 99987961 is about 464.1402559177.

The spelling of 99987961 in words is "ninety-nine million, nine hundred eighty-seven thousand, nine hundred sixty-one".