99967981 has 2 divisors, whose sum is σ = 99967982. Its totient is φ = 99967980.

The previous prime is 99967961. The next prime is 99967993. The reversal of 99967981 is 18976999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 97515625 + 2452356 = 9875^2 + 1566^2 .

It is an emirp because it is prime and its reverse (18976999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99967981 - 2¹³ = 99959789 is a prime.

It is a super-2 number, since 2×99967981² = 19987194450432722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99967961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49983990 + 49983991.

It is an arithmetic number, because the mean of its divisors is an integer number (49983991).

Almost surely, 2^99967981 is an apocalyptic number.

It is an amenable number.

99967981 is a deficient number, since it is larger than the sum of its proper divisors (1).

99967981 is an equidigital number, since it uses as much as digits as its factorization.

99967981 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 99967981 is about 9998.3989218274. The cubic root of 99967981 is about 464.1093383953.

The spelling of 99967981 in words is "ninety-nine million, nine hundred sixty-seven thousand, nine hundred eighty-one".