1001720844 has 72 divisors (see below), whose sum is σ = 2646291648. Its totient is φ = 331315920.

The previous prime is 1001720803. The next prime is 1001720849. The reversal of 1001720844 is 4480271001.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1001720849) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 123399 + ... + 131265.

Almost surely, 2^1001720844 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 1001720844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1323145824).

1001720844 is an abundant number, since it is smaller than the sum of its proper divisors (1644570804).

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

1001720844 is a wasteful number, since it uses less digits than its factorization.

1001720844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8017 (or 8003 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 1001720844 is about 31649.9738388517. The cubic root of 1001720844 is about 1000.5732859471.

Adding to 1001720844 its reverse (4480271001), we get a palindrome (5481991845).

The spelling of 1001720844 in words is "one billion, one million, seven hundred twenty thousand, eight hundred forty-four".