999640428 has 48 divisors (see below), whose sum is σ = 2376514560. Its totient is φ = 326952000.

The previous prime is 999640403. The next prime is 999640459. The reversal of 999640428 is 824046999.

It is a happy number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 349203 + ... + 352053.

It is an arithmetic number, because the mean of its divisors is an integer number (49510720).

Almost surely, 2^999640428 is an apocalyptic number.

It is an amenable number.

999640428 is an abundant number, since it is smaller than the sum of its proper divisors (1376874132).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999640428 is a wasteful number, since it uses less digits than its factorization.

999640428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3398 (or 3396 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 51.

The square root of 999640428 is about 31617.0907580062. The cubic root of 999640428 is about 999.8801282980.

The spelling of 999640428 in words is "nine hundred ninety-nine million, six hundred forty thousand, four hundred twenty-eight".