99876781 has 2 divisors, whose sum is σ = 99876782. Its totient is φ = 99876780.

The previous prime is 99876709. The next prime is 99876827. The reversal of 99876781 is 18767899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 97831881 + 2044900 = 9891^2 + 1430^2 .

It is a cyclic number.

It is not a de Polignac number, because 99876781 - 2²⁵ = 66322349 is a prime.

It is a super-2 number, since 2×99876781² = 19950742765843922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99876181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49938390 + 49938391.

It is an arithmetic number, because the mean of its divisors is an integer number (49938391).

Almost surely, 2^99876781 is an apocalyptic number.

It is an amenable number.

99876781 is a deficient number, since it is larger than the sum of its proper divisors (1).

99876781 is an equidigital number, since it uses as much as digits as its factorization.

99876781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1524096, while the sum is 55.

The square root of 99876781 is about 9993.8371509646. The cubic root of 99876781 is about 463.9681610263.

It can be divided in two parts, 9 and 9876781, that added together give a triangular number (9876790 = T₄₄₄₄).

The spelling of 99876781 in words is "ninety-nine million, eight hundred seventy-six thousand, seven hundred eighty-one".