998472721 has 4 divisors (see below), whose sum is σ = 1001350512. Its totient is φ = 995594932.

The previous prime is 998472623. The next prime is 998472731. The reversal of 998472721 is 127274899.

998472721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 127274899 = 911 ⋅139709.

It is a cyclic number.

It is not a de Polignac number, because 998472721 - 2²⁵ = 964918289 is a prime.

It is a super-2 number, since 2×998472721² = 1993895549162287682, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (998472731) 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, 1438375 + ... + 1439068.

It is an arithmetic number, because the mean of its divisors is an integer number (250337628).

Almost surely, 2^998472721 is an apocalyptic number.

It is an amenable number.

998472721 is a deficient number, since it is larger than the sum of its proper divisors (2877791).

998472721 is a wasteful number, since it uses less digits than its factorization.

998472721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2877790.

The product of its digits is 508032, while the sum is 49.

The square root of 998472721 is about 31598.6189729868. The cubic root of 998472721 is about 999.4906476042.

The spelling of 998472721 in words is "nine hundred ninety-eight million, four hundred seventy-two thousand, seven hundred twenty-one".