999621956 has 24 divisors (see below), whose sum is σ = 1767720024. Its totient is φ = 494574080.

The previous prime is 999621937. The next prime is 999621971. The reversal of 999621956 is 659126999.

It can be written as a sum of positive squares in 4 ways, for example, as 28302400 + 971319556 = 5320^2 + 31166^2 .

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 347966 + ... + 350826.

It is an arithmetic number, because the mean of its divisors is an integer number (73655001).

Almost surely, 2^999621956 is an apocalyptic number.

It is an amenable number.

999621956 is a deficient number, since it is larger than the sum of its proper divisors (768098068).

999621956 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (999621955) it forms an eRAP, since the sums of their prime factors are consecutive (3750 and 3751).

999621956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3751 (or 3749 counting only the distinct ones).

The product of its digits is 2361960, while the sum is 56.

The square root of 999621956 is about 31616.7986361681. The cubic root of 999621956 is about 999.8739694503.

The spelling of 999621956 in words is "nine hundred ninety-nine million, six hundred twenty-one thousand, nine hundred fifty-six".