991023433 has 4 divisors (see below), whose sum is σ = 991788820. Its totient is φ = 990258048.

The previous prime is 991023431. The next prime is 991023443. The reversal of 991023433 is 334320199.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 640697344 + 350326089 = 25312^2 + 18717^2 .

It is a cyclic number.

It is not a de Polignac number, because 991023433 - 2¹ = 991023431 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991023431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 380748 + ... + 383341.

It is an arithmetic number, because the mean of its divisors is an integer number (247947205).

Almost surely, 2^991023433 is an apocalyptic number.

It is an amenable number.

991023433 is a deficient number, since it is larger than the sum of its proper divisors (765387).

991023433 is a wasteful number, since it uses less digits than its factorization.

991023433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765386.

The product of its (nonzero) digits is 17496, while the sum is 34.

The square root of 991023433 is about 31480.5246620827. The cubic root of 991023433 is about 996.9988128866.

The spelling of 991023433 in words is "nine hundred ninety-one million, twenty-three thousand, four hundred thirty-three".