1005781021 has 8 divisors (see below), whose sum is σ = 1159637184. Its totient is φ = 854468160.

The previous prime is 1005781003. The next prime is 1005781031. The reversal of 1005781021 is 1201875001.

1005781021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1005781021 - 2¹³ = 1005772829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1005781031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 634975 + ... + 636556.

It is an arithmetic number, because the mean of its divisors is an integer number (144954648).

Almost surely, 2^1005781021 is an apocalyptic number.

It is an amenable number.

1005781021 is a deficient number, since it is larger than the sum of its proper divisors (153856163).

1005781021 is a wasteful number, since it uses less digits than its factorization.

1005781021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1271651.

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 1005781021 is about 31714.0508450119. The cubic root of 1005781021 is about 1001.9233055244.

The spelling of 1005781021 in words is "one billion, five million, seven hundred eighty-one thousand, twenty-one".