669611561 has 4 divisors (see below), whose sum is σ = 670975824. Its totient is φ = 668247300.

The previous prime is 669611543. The next prime is 669611567. The reversal of 669611561 is 165116966.

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 not a de Polignac number, because 669611561 - 2¹⁰ = 669610537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669611567) 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 3 ways as a sum of consecutive naturals, for example, 681395 + ... + 682376.

It is an arithmetic number, because the mean of its divisors is an integer number (167743956).

Almost surely, 2^669611561 is an apocalyptic number.

It is an amenable number.

669611561 is a deficient number, since it is larger than the sum of its proper divisors (1364263).

669611561 is a wasteful number, since it uses less digits than its factorization.

669611561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1364262.

The product of its digits is 58320, while the sum is 41.

The square root of 669611561 is about 25876.8537693438. The cubic root of 669611561 is about 874.8648764405.

The spelling of 669611561 in words is "six hundred sixty-nine million, six hundred eleven thousand, five hundred sixty-one".