1001989440 has 560 divisors, whose sum is σ = 3894612480. Its totient is φ = 243855360.

The previous prime is 1001989427. The next prime is 1001989451. The reversal of 1001989440 is 449891001.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1001989395 and 1001989404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 23302059 + ... + 23302101.

Almost surely, 2^1001989440 is an apocalyptic number.

1001989440 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 1001989440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1947306240).

1001989440 is an abundant number, since it is smaller than the sum of its proper divisors (2892623040).

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

1001989440 is a wasteful number, since it uses less digits than its factorization.

1001989440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 1001989440 is about 31654.2167807071. The cubic root of 1001989440 is about 1000.6627073886.

The spelling of 1001989440 in words is "one billion, one million, nine hundred eighty-nine thousand, four hundred forty".