921989 has 2 divisors, whose sum is σ = 921990. Its totient is φ = 921988.

The previous prime is 921959. The next prime is 922021. The reversal of 921989 is 989129.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 917764 + 4225 = 958^2 + 65^2 .

It is a cyclic number.

It is not a de Polignac number, because 921989 - 2⁸ = 921733 is a prime.

It is a super-2 number, since 2×921989² = 1700127432242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 921989.

It is not a weakly prime, because it can be changed into another prime (921919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460994 + 460995.

It is an arithmetic number, because the mean of its divisors is an integer number (460995).

2⁹²¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

921989 is a deficient number, since it is larger than the sum of its proper divisors (1).

921989 is an equidigital number, since it uses as much as digits as its factorization.

921989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 38.

The square root of 921989 is about 960.2025827918. The cubic root of 921989 is about 97.3289219973.

The spelling of 921989 in words is "nine hundred twenty-one thousand, nine hundred eighty-nine".