1001021001985 has 16 divisors (see below), whose sum is σ = 1204526608272. Its totient is φ = 798618528000.

The previous prime is 1001021001973. The next prime is 1001021001989. The reversal of 1001021001985 is 5891001201001.

It can be written as a sum of positive squares in 8 ways, for example, as 3827030769 + 997193971216 = 61863^2 + 998596^2 .

It is not a de Polignac number, because 1001021001985 - 2¹³ = 1001020993793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1001021001989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2855835 + ... + 3187135.

It is an arithmetic number, because the mean of its divisors is an integer number (75282913017).

Almost surely, 2^{1001021001985} is an apocalyptic number.

It is an amenable number.

1001021001985 is a deficient number, since it is larger than the sum of its proper divisors (203505606287).

1001021001985 is a wasteful number, since it uses less digits than its factorization.

1001021001985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332964.

The product of its (nonzero) digits is 720, while the sum is 28.

Adding to 1001021001985 its reverse (5891001201001), we get a palindrome (6892022202986).

The spelling of 1001021001985 in words is "one trillion, one billion, twenty-one million, one thousand, nine hundred eighty-five".