1999100101 has 2 divisors, whose sum is σ = 1999100102. Its totient is φ = 1999100100.

The previous prime is 1999100011. The next prime is 1999100107. The reversal of 1999100101 is 1010019991.

Together with previous prime (1999100011) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1762740225 + 236359876 = 41985^2 + 15374^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999100101 - 2⁹ = 1999099589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999100107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999550050 + 999550051.

It is an arithmetic number, because the mean of its divisors is an integer number (999550051).

Almost surely, 2^1999100101 is an apocalyptic number.

1999100101 is the 19996-th centered decagonal number.

It is an amenable number.

1999100101 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999100101 is an equidigital number, since it uses as much as digits as its factorization.

1999100101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 729, while the sum is 31.

The square root of 1999100101 is about 44711.2972413013. The cubic root of 1999100101 is about 1259.7320545971.

The spelling of 1999100101 in words is "one billion, nine hundred ninety-nine million, one hundred thousand, one hundred one".