861209605 has 8 divisors (see below), whose sum is σ = 1066788864. Its totient is φ = 666742800.

The previous prime is 861209603. The next prime is 861209617. The reversal of 861209605 is 506902168.

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

It is not a de Polignac number, because 861209605 - 2¹ = 861209603 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861209603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2777941 + ... + 2778250.

It is an arithmetic number, because the mean of its divisors is an integer number (133348608).

Almost surely, 2^861209605 is an apocalyptic number.

It is an amenable number.

861209605 is a deficient number, since it is larger than the sum of its proper divisors (205579259).

861209605 is a wasteful number, since it uses less digits than its factorization.

861209605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5556227.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 861209605 is about 29346.3729445395. The cubic root of 861209605 is about 951.4141837165.

The spelling of 861209605 in words is "eight hundred sixty-one million, two hundred nine thousand, six hundred five".