890021805 has 16 divisors (see below), whose sum is σ = 1440037440. Its totient is φ = 469344128.

The previous prime is 890021801. The next prime is 890021819. The reversal of 890021805 is 508120098.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 890021805 - 2² = 890021801 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (890021801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 332007 + ... + 334676.

It is an arithmetic number, because the mean of its divisors is an integer number (90002340).

Almost surely, 2^890021805 is an apocalyptic number.

It is an amenable number.

890021805 is a deficient number, since it is larger than the sum of its proper divisors (550015635).

890021805 is a wasteful number, since it uses less digits than its factorization.

890021805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 666780.

The product of its (nonzero) digits is 5760, while the sum is 33.

The square root of 890021805 is about 29833.2332307445. The cubic root of 890021805 is about 961.9080270616.

The spelling of 890021805 in words is "eight hundred ninety million, twenty-one thousand, eight hundred five".