991766653 has 4 divisors (see below), whose sum is σ = 992174400. Its totient is φ = 991358908.

The previous prime is 991766651. The next prime is 991766669. The reversal of 991766653 is 356667199.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 356667199 = 7 ⋅50952457.

It is a cyclic number.

It is not a de Polignac number, because 991766653 - 2¹ = 991766651 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 991766653.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991766651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 200203 + ... + 205096.

It is an arithmetic number, because the mean of its divisors is an integer number (248043600).

Almost surely, 2^991766653 is an apocalyptic number.

It is an amenable number.

991766653 is a deficient number, since it is larger than the sum of its proper divisors (407747).

991766653 is a wasteful number, since it uses less digits than its factorization.

991766653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407746.

The product of its digits is 1837080, while the sum is 52.

The square root of 991766653 is about 31492.3268908476. The cubic root of 991766653 is about 997.2479843574.

The spelling of 991766653 in words is "nine hundred ninety-one million, seven hundred sixty-six thousand, six hundred fifty-three".