1021001666 has 8 divisors (see below), whose sum is σ = 1584313020. Its totient is φ = 492897328.

The previous prime is 1021001629. The next prime is 1021001693. The reversal of 1021001666 is 6661001201.

It can be written as a sum of positive squares in 2 ways, for example, as 999887641 + 21114025 = 31621^2 + 4595^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8801681 + ... + 8801796.

Almost surely, 2^1021001666 is an apocalyptic number.

1021001666 is a deficient number, since it is larger than the sum of its proper divisors (563311354).

1021001666 is a wasteful number, since it uses less digits than its factorization.

1021001666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17603508.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 1021001666 is about 31953.1166867960. The cubic root of 1021001666 is about 1006.9521114765.

Adding to 1021001666 its reverse (6661001201), we get a palindrome (7682002867).

The spelling of 1021001666 in words is "one billion, twenty-one million, one thousand, six hundred sixty-six".