99673781 has 2 divisors, whose sum is σ = 99673782. Its totient is φ = 99673780.

The previous prime is 99673759. The next prime is 99673799. The reversal of 99673781 is 18737699.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58828900 + 40844881 = 7670^2 + 6391^2 .

It is a cyclic number.

It is not a de Polignac number, because 99673781 - 2²² = 95479477 is a prime.

It is a super-2 number, since 2×99673781² = 19869725237671922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99673751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49836890 + 49836891.

It is an arithmetic number, because the mean of its divisors is an integer number (49836891).

Almost surely, 2^99673781 is an apocalyptic number.

It is an amenable number.

99673781 is a deficient number, since it is larger than the sum of its proper divisors (1).

99673781 is an equidigital number, since it uses as much as digits as its factorization.

99673781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 571536, while the sum is 50.

The square root of 99673781 is about 9983.6757259038. The cubic root of 99673781 is about 463.6536087058.

The spelling of 99673781 in words is "ninety-nine million, six hundred seventy-three thousand, seven hundred eighty-one".