1021660625 has 10 divisors (see below), whose sum is σ = 1276667898. Its totient is φ = 817328000.

The previous prime is 1021660603. The next prime is 1021660631. The reversal of 1021660625 is 5260661201.

It can be written as a sum of positive squares in 5 ways, for example, as 211062784 + 810597841 = 14528^2 + 28471^2 .

It is not a de Polignac number, because 1021660625 - 2⁶ = 1021660561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 816704 + ... + 817953.

Almost surely, 2^1021660625 is an apocalyptic number.

It is an amenable number.

1021660625 is a deficient number, since it is larger than the sum of its proper divisors (255007273).

1021660625 is an frugal number, since it uses more digits than its factorization.

1021660625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1634677 (or 1634662 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 1021660625 is about 31963.4263651443. The cubic root of 1021660625 is about 1007.1686953402.

The spelling of 1021660625 in words is "one billion, twenty-one million, six hundred sixty thousand, six hundred twenty-five".