1998647790 has 64 divisors (see below), whose sum is σ = 5042082816. Its totient is φ = 506054912.

The previous prime is 1998647711. The next prime is 1998647803. The reversal of 1998647790 is 977468991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 83959 + ... + 105101.

It is an arithmetic number, because the mean of its divisors is an integer number (78782544).

Almost surely, 2^1998647790 is an apocalyptic number.

1998647790 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1998647790, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2521041408).

1998647790 is an abundant number, since it is smaller than the sum of its proper divisors (3043435026).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1998647790 is a wasteful number, since it uses less digits than its factorization.

1998647790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21313.

The product of its (nonzero) digits is 6858432, while the sum is 60.

The square root of 1998647790 is about 44706.2388263652. The cubic root of 1998647790 is about 1259.6370395712.

It can be divided in two parts, 19986 and 47790, that added together give a palindrome (67776).

The spelling of 1998647790 in words is "one billion, nine hundred ninety-eight million, six hundred forty-seven thousand, seven hundred ninety".