855601921 has 16 divisors (see below), whose sum is σ = 882800640. Its totient is φ = 828938880.

The previous prime is 855601919. The next prime is 855601927. The reversal of 855601921 is 129106558.

It is a cyclic number.

It is not a de Polignac number, because 855601921 - 2¹ = 855601919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (855601927) 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 15 ways as a sum of consecutive naturals, for example, 1386405 + ... + 1387021.

It is an arithmetic number, because the mean of its divisors is an integer number (55175040).

Almost surely, 2^855601921 is an apocalyptic number.

It is an amenable number.

855601921 is a deficient number, since it is larger than the sum of its proper divisors (27198719).

855601921 is a wasteful number, since it uses less digits than its factorization.

855601921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 984.

The product of its (nonzero) digits is 21600, while the sum is 37.

The square root of 855601921 is about 29250.6738554858. The cubic root of 855601921 is about 949.3446712216.

The spelling of 855601921 in words is "eight hundred fifty-five million, six hundred one thousand, nine hundred twenty-one".