100399905 has 20 divisors (see below), whose sum is σ = 179976852. Its totient is φ = 53546400.

The previous prime is 100399903. The next prime is 100399927. The reversal of 100399905 is 509993001.

It can be written as a sum of positive squares in 2 ways, for example, as 30041361 + 70358544 = 5481^2 + 8388^2 .

It is not a de Polignac number, because 100399905 - 2¹ = 100399903 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 100399905.

It is not an unprimeable number, because it can be changed into a prime (100399903) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 123546 + ... + 124355.

Almost surely, 2^100399905 is an apocalyptic number.

100399905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

100399905 is a deficient number, since it is larger than the sum of its proper divisors (79576947).

100399905 is an equidigital number, since it uses as much as digits as its factorization.

100399905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247918 (or 247909 counting only the distinct ones).

The product of its (nonzero) digits is 10935, while the sum is 36.

The square root of 100399905 is about 10019.9752993708. The cubic root of 100399905 is about 464.7767919369.

The spelling of 100399905 in words is "one hundred million, three hundred ninety-nine thousand, nine hundred five".