1989494640 has 240 divisors, whose sum is σ = 7660224000. Its totient is φ = 453293568.

The previous prime is 1989494609. The next prime is 1989494651. The reversal of 1989494640 is 464949891.

It is a happy number.

1989494640 is a `hidden beast` number, since 1 + 98 + 9 + 494 + 64 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3018631 + ... + 3019289.

It is an arithmetic number, because the mean of its divisors is an integer number (31917600).

Almost surely, 2^1989494640 is an apocalyptic number.

1989494640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1989494640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3830112000).

1989494640 is an abundant number, since it is smaller than the sum of its proper divisors (5670729360).

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

1989494640 is a wasteful number, since it uses less digits than its factorization.

1989494640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1284 (or 1275 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 54.

The square root of 1989494640 is about 44603.7514117367. The cubic root of 1989494640 is about 1257.7111887687.

The spelling of 1989494640 in words is "one billion, nine hundred eighty-nine million, four hundred ninety-four thousand, six hundred forty".