189896821 has 2 divisors, whose sum is σ = 189896822. Its totient is φ = 189896820.

The previous prime is 189896807. The next prime is 189896881. The reversal of 189896821 is 128698981.

189896821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 141871921 + 48024900 = 11911^2 + 6930^2 .

It is an emirp because it is prime and its reverse (128698981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 189896821 - 2¹¹ = 189894773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (189896801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94948410 + 94948411.

It is an arithmetic number, because the mean of its divisors is an integer number (94948411).

Almost surely, 2^189896821 is an apocalyptic number.

It is an amenable number.

189896821 is a deficient number, since it is larger than the sum of its proper divisors (1).

189896821 is an equidigital number, since it uses as much as digits as its factorization.

189896821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 497664, while the sum is 52.

The square root of 189896821 is about 13780.3055481364. The cubic root of 189896821 is about 574.7856249372.

The spelling of 189896821 in words is "one hundred eighty-nine million, eight hundred ninety-six thousand, eight hundred twenty-one".