4998721991 has 4 divisors (see below), whose sum is σ = 5000956800. Its totient is φ = 4996487184.

The previous prime is 4998721979. The next prime is 4998721999. The reversal of 4998721991 is 1991278994.

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

It is a cyclic number.

It is not a de Polignac number, because 4998721991 - 2³⁰ = 3924980167 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 4998721991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4998721999) 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, 1114046 + ... + 1118523.

It is an arithmetic number, because the mean of its divisors is an integer number (1250239200).

Almost surely, 2^4998721991 is an apocalyptic number.

4998721991 is a deficient number, since it is larger than the sum of its proper divisors (2234809).

4998721991 is a wasteful number, since it uses less digits than its factorization.

4998721991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2234808.

The product of its digits is 2939328, while the sum is 59.

The square root of 4998721991 is about 70701.6406528165. The cubic root of 4998721991 is about 1709.8302432853.

The spelling of 4998721991 in words is "four billion, nine hundred ninety-eight million, seven hundred twenty-one thousand, nine hundred ninety-one".