991906769 has 16 divisors (see below), whose sum is σ = 1208261376. Its totient is φ = 794880000.

The previous prime is 991906679. The next prime is 991906777. The reversal of 991906769 is 967609199.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 991906769 - 2¹² = 991902673 is a prime.

It is a super-2 number, since 2×991906769² = 1967758076776038722, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (991906469) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9632 + ... + 45569.

It is an arithmetic number, because the mean of its divisors is an integer number (75516336).

Almost surely, 2^991906769 is an apocalyptic number.

It is an amenable number.

991906769 is a deficient number, since it is larger than the sum of its proper divisors (216354607).

991906769 is a wasteful number, since it uses less digits than its factorization.

991906769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55376.

The product of its (nonzero) digits is 1653372, while the sum is 56.

The square root of 991906769 is about 31494.5514176659. The cubic root of 991906769 is about 997.2949456120.

The spelling of 991906769 in words is "nine hundred ninety-one million, nine hundred six thousand, seven hundred sixty-nine".