1021610561 has 4 divisors (see below), whose sum is σ = 1022408112. Its totient is φ = 1020813012.

The previous prime is 1021610539. The next prime is 1021610609. The reversal of 1021610561 is 1650161201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1021610561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1021610501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 396851 + ... + 399416.

It is an arithmetic number, because the mean of its divisors is an integer number (255602028).

Almost surely, 2^1021610561 is an apocalyptic number.

It is an amenable number.

1021610561 is a deficient number, since it is larger than the sum of its proper divisors (797551).

1021610561 is an equidigital number, since it uses as much as digits as its factorization.

1021610561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 797550.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 1021610561 is about 31962.6432104731. The cubic root of 1021610561 is about 1007.1522437855.

Adding to 1021610561 its reverse (1650161201), we get a palindrome (2671771762).

The spelling of 1021610561 in words is "one billion, twenty-one million, six hundred ten thousand, five hundred sixty-one".