1020645 has 24 divisors (see below), whose sum is σ = 1819896. Its totient is φ = 528768.

The previous prime is 1020631. The next prime is 1020667. The reversal of 1020645 is 5460201.

It is a happy number.

1020645 is a `hidden beast` number, since 1 + 0 + 20 + 645 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 34596 + 986049 = 186^2 + 993^2 .

It is not a de Polignac number, because 1020645 - 2⁷ = 1020517 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1359 + ... + 1971.

It is an arithmetic number, because the mean of its divisors is an integer number (75829).

2^1020645 is an apocalyptic number.

1020645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1020645 is a deficient number, since it is larger than the sum of its proper divisors (799251).

1020645 is a wasteful number, since it uses less digits than its factorization.

1020645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661 (or 658 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 1020645 is about 1010.2697659536. The cubic root of 1020645 is about 100.6834845129.

Adding to 1020645 its reverse (5460201), we get a palindrome (6480846).

The spelling of 1020645 in words is "one million, twenty thousand, six hundred forty-five".