1998779436 has 96 divisors (see below), whose sum is σ = 5437429760. Its totient is φ = 634132800.

The previous prime is 1998779429. The next prime is 1998779567. The reversal of 1998779436 is 6349778991.

1998779436 is a `hidden beast` number, since 199 + 8 + 7 + 7 + 9 + 436 = 666.

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, 199335 + ... + 209121.

Almost surely, 2^1998779436 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1998779436, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2718714880).

1998779436 is an abundant number, since it is smaller than the sum of its proper divisors (3438650324).

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

1998779436 is a wasteful number, since it uses less digits than its factorization.

1998779436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9892 (or 9884 counting only the distinct ones).

The product of its digits is 20575296, while the sum is 63.

The square root of 1998779436 is about 44707.7111469599. The cubic root of 1998779436 is about 1259.6646953589.

The spelling of 1998779436 in words is "one billion, nine hundred ninety-eight million, seven hundred seventy-nine thousand, four hundred thirty-six".