3999999945 has 16 divisors (see below), whose sum is σ = 6406911360. Its totient is φ = 2131029504.

The previous prime is 3999999937. The next prime is 3999999979. The reversal of 3999999945 is 5499999993.

It is a happy number.

It is not a de Polignac number, because 3999999945 - 2³ = 3999999937 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129589 + ... + 157458.

It is an arithmetic number, because the mean of its divisors is an integer number (400431960).

Almost surely, 2^3999999945 is an apocalyptic number.

It is an amenable number.

3999999945 is a deficient number, since it is larger than the sum of its proper divisors (2406911415).

3999999945 is a wasteful number, since it uses less digits than its factorization.

3999999945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287984.

The product of its digits is 286978140, while the sum is 75.

The square root of 3999999945 is about 63245.5527685544. The cubic root of 3999999945 is about 1587.4010446926.

The spelling of 3999999945 in words is "three billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred forty-five".