2021000781 has 8 divisors (see below), whose sum is σ = 2727133920. Its totient is φ = 1331100752.

The previous prime is 2021000747. The next prime is 2021000789. The reversal of 2021000781 is 1870001202.

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

It is a cyclic number.

It is not a de Polignac number, because 2021000781 - 2⁹ = 2021000269 is a prime.

It is a super-2 number, since 2×2021000781² = 8168888313605219922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021000789) 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, 4057986 + ... + 4058483.

It is an arithmetic number, because the mean of its divisors is an integer number (340891740).

Almost surely, 2^2021000781 is an apocalyptic number.

It is an amenable number.

2021000781 is a deficient number, since it is larger than the sum of its proper divisors (706133139).

2021000781 is an equidigital number, since it uses as much as digits as its factorization.

2021000781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8116555.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 2021000781 is about 44955.5422723383. The cubic root of 2021000781 is about 1264.3155918047.

Adding to 2021000781 its reverse (1870001202), we get a palindrome (3891001983).

The spelling of 2021000781 in words is "two billion, twenty-one million, seven hundred eighty-one", and thus it is an aban number.