10991857990 has 8 divisors (see below), whose sum is σ = 19785344400. Its totient is φ = 4396743192.

The previous prime is 10991857969. The next prime is 10991858029. The reversal of 10991857990 is 9975819901.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 549592890 + ... + 549592909.

It is an arithmetic number, because the mean of its divisors is an integer number (2473168050).

Almost surely, 2^10991857990 is an apocalyptic number.

10991857990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

10991857990 is a deficient number, since it is larger than the sum of its proper divisors (8793486410).

10991857990 is a wasteful number, since it uses less digits than its factorization.

10991857990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1099185806.

The product of its (nonzero) digits is 1837080, while the sum is 58.

The spelling of 10991857990 in words is "ten billion, nine hundred ninety-one million, eight hundred fifty-seven thousand, nine hundred ninety".