998820251 has 18 divisors (see below), whose sum is σ = 1181498508. Its totient is φ = 837027360.

The previous prime is 998820239. The next prime is 998820259. The reversal of 998820251 is 152028899.

It is a de Polignac number, because none of the positive numbers 2^k-998820251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (998820259) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1362281 + ... + 1363013.

It is an arithmetic number, because the mean of its divisors is an integer number (65638806).

Almost surely, 2^998820251 is an apocalyptic number.

998820251 is a deficient number, since it is larger than the sum of its proper divisors (182678257).

998820251 is an equidigital number, since it uses as much as digits as its factorization.

998820251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1503 (or 757 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 44.

The square root of 998820251 is about 31604.1176272966. The cubic root of 998820251 is about 999.6065955866.

Multiplying 998820251 by its sum of digits (44), we get a square (43948091044 = 209638²).

The spelling of 998820251 in words is "nine hundred ninety-eight million, eight hundred twenty thousand, two hundred fifty-one".