861998101 has 2 divisors, whose sum is σ = 861998102. Its totient is φ = 861998100.

The previous prime is 861998087. The next prime is 861998119. The reversal of 861998101 is 101899168.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 588062500 + 273935601 = 24250^2 + 16551^2 .

It is a cyclic number.

It is not a de Polignac number, because 861998101 - 2⁵ = 861998069 is a prime.

It is a super-2 number, since 2×861998101² = 1486081452255212402, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861998191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430999050 + 430999051.

It is an arithmetic number, because the mean of its divisors is an integer number (430999051).

Almost surely, 2^861998101 is an apocalyptic number.

It is an amenable number.

861998101 is a deficient number, since it is larger than the sum of its proper divisors (1).

861998101 is an equidigital number, since it uses as much as digits as its factorization.

861998101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 43.

The square root of 861998101 is about 29359.8041716902. The cubic root of 861998101 is about 951.7044566231.

The spelling of 861998101 in words is "eight hundred sixty-one million, nine hundred ninety-eight thousand, one hundred one".