991909802 has 32 divisors (see below), whose sum is σ = 1644817104. Its totient is φ = 445708800.

The previous prime is 991909777. The next prime is 991909811. The reversal of 991909802 is 208909199.

It can be written as a sum of positive squares in 8 ways, for example, as 295530481 + 696379321 = 17191^2 + 26389^2 .

It is a super-3 number, since 3×991909802³ (a number of 28 digits) contains 333 as substring.

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, 934352 + ... + 935412.

Almost surely, 2^991909802 is an apocalyptic number.

991909802 is a deficient number, since it is larger than the sum of its proper divisors (652907302).

991909802 is a wasteful number, since it uses less digits than its factorization.

991909802 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1994.

The product of its (nonzero) digits is 104976, while the sum is 47.

The square root of 991909802 is about 31494.5995688150. The cubic root of 991909802 is about 997.2959621029.

The spelling of 991909802 in words is "nine hundred ninety-one million, nine hundred nine thousand, eight hundred two".