125999999 has 4 divisors (see below), whose sum is σ = 127880664. Its totient is φ = 124119336.

The previous prime is 125999959. The next prime is 126000013. The reversal of 125999999 is 999999521.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 125999999 - 2¹⁶ = 125934463 is a prime.

It is a Duffinian number.

125999999 is a modest number, since divided by 99999 gives 1259 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (125999959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 940232 + ... + 940365.

It is an arithmetic number, because the mean of its divisors is an integer number (31970166).

Almost surely, 2^125999999 is an apocalyptic number.

125999999 is a deficient number, since it is larger than the sum of its proper divisors (1880665).

125999999 is an equidigital number, since it uses as much as digits as its factorization.

125999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1880664.

The product of its digits is 5314410, while the sum is 62.

The square root of 125999999 is about 11224.9721157783. The cubic root of 125999999 is about 501.3297921702.

The spelling of 125999999 in words is "one hundred twenty-five million, nine hundred ninety-nine thousand, nine hundred ninety-nine".