1021605664 has 12 divisors (see below), whose sum is σ = 2011286214. Its totient is φ = 510802816.

The previous prime is 1021605617. The next prime is 1021605671. The reversal of 1021605664 is 4665061201.

1021605664 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 650658064 + 370947600 = 25508^2 + 19260^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15962557 + ... + 15962620.

Almost surely, 2^1021605664 is an apocalyptic number.

It is an amenable number.

1021605664 is a deficient number, since it is larger than the sum of its proper divisors (989680550).

1021605664 is an equidigital number, since it uses as much as digits as its factorization.

1021605664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31925187 (or 31925179 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 1021605664 is about 31962.5666053276. The cubic root of 1021605664 is about 1007.1506345511.

Adding to 1021605664 its reverse (4665061201), we get a palindrome (5686666865).

The spelling of 1021605664 in words is "one billion, twenty-one million, six hundred five thousand, six hundred sixty-four".