1021660394 has 4 divisors (see below), whose sum is σ = 1532490594. Its totient is φ = 510830196.

The previous prime is 1021660313. The next prime is 1021660403. The reversal of 1021660394 is 4930661201.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 743271169 + 278389225 = 27263^2 + 16685^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1021660394.

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 as a sum of consecutive naturals, namely, 255415097 + ... + 255415100.

Almost surely, 2^1021660394 is an apocalyptic number.

1021660394 is a deficient number, since it is larger than the sum of its proper divisors (510830200).

1021660394 is an equidigital number, since it uses as much as digits as its factorization.

1021660394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510830199.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 1021660394 is about 31963.4227516391. The cubic root of 1021660394 is about 1007.1686194325.

The spelling of 1021660394 in words is "one billion, twenty-one million, six hundred sixty thousand, three hundred ninety-four".