1989961440 has 192 divisors, whose sum is σ = 6597158400. Its totient is φ = 503465984.

The previous prime is 1989961429. The next prime is 1989961451. The reversal of 1989961440 is 441699891.

It is an interprime number because it is at equal distance from previous prime (1989961429) and next prime (1989961451).

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, 820069 + ... + 822491.

It is an arithmetic number, because the mean of its divisors is an integer number (34360200).

Almost surely, 2^1989961440 is an apocalyptic number.

1989961440 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 1989961440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3298579200).

1989961440 is an abundant number, since it is smaller than the sum of its proper divisors (4607196960).

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

1989961440 is a wasteful number, since it uses less digits than its factorization.

1989961440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2529 (or 2521 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 51.

The square root of 1989961440 is about 44608.9838485478. The cubic root of 1989961440 is about 1257.8095476952.

The spelling of 1989961440 in words is "one billion, nine hundred eighty-nine million, nine hundred sixty-one thousand, four hundred forty".