1001021985 has 24 divisors (see below), whose sum is σ = 1810545984. Its totient is φ = 510665760.

The previous prime is 1001021981. The next prime is 1001022007. The reversal of 1001021985 is 5891201001.

It is not a de Polignac number, because 1001021985 - 2² = 1001021981 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1001021981) 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, 482551 + ... + 484620.

It is an arithmetic number, because the mean of its divisors is an integer number (75439416).

Almost surely, 2^1001021985 is an apocalyptic number.

1001021985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1001021985 is a deficient number, since it is larger than the sum of its proper divisors (809523999).

1001021985 is a wasteful number, since it uses less digits than its factorization.

1001021985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 967205 (or 967202 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 1001021985 is about 31638.9314769004. The cubic root of 1001021985 is about 1000.3405456821.

Adding to 1001021985 its reverse (5891201001), we get a palindrome (6892222986).

The spelling of 1001021985 in words is "one billion, one million, twenty-one thousand, nine hundred eighty-five".