999981604 has 6 divisors (see below), whose sum is σ = 1749967814. Its totient is φ = 499990800.

The previous prime is 999981551. The next prime is 999981607. The reversal of 999981604 is 406189999.

It can be written as a sum of positive squares in only one way, i.e., 652904704 + 347076900 = 25552^2 + 18630^2 .

It is not an unprimeable number, because it can be changed into a prime (999981607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124997697 + ... + 124997704.

Almost surely, 2^999981604 is an apocalyptic number.

It is an amenable number.

999981604 is a deficient number, since it is larger than the sum of its proper divisors (749986210).

999981604 is a wasteful number, since it uses less digits than its factorization.

999981604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249995405 (or 249995403 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 55.

The square root of 999981604 is about 31622.4857340469. The cubic root of 999981604 is about 999.9938679624.

The spelling of 999981604 in words is "nine hundred ninety-nine million, nine hundred eighty-one thousand, six hundred four".