1020645491 has 8 divisors (see below), whose sum is σ = 1025515344. Its totient is φ = 1015787520.

The previous prime is 1020645487. The next prime is 1020645523. The reversal of 1020645491 is 1945460201.

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

It is a cyclic number.

It is not a de Polignac number, because 1020645491 - 2² = 1020645487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1020645421) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 201176 + ... + 206186.

It is an arithmetic number, because the mean of its divisors is an integer number (128189418).

Almost surely, 2^1020645491 is an apocalyptic number.

1020645491 is a deficient number, since it is larger than the sum of its proper divisors (4869853).

1020645491 is an equidigital number, since it uses as much as digits as its factorization.

1020645491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5941.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 1020645491 is about 31947.5428006600. The cubic root of 1020645491 is about 1006.8350065807.

The spelling of 1020645491 in words is "one billion, twenty million, six hundred forty-five thousand, four hundred ninety-one".