984187921 has 2 divisors, whose sum is σ = 984187922. Its totient is φ = 984187920.

The previous prime is 984187873. The next prime is 984187933. The reversal of 984187921 is 129781489.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 970945600 + 13242321 = 31160^2 + 3639^2 .

It is an emirp because it is prime and its reverse (129781489) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 984187921 - 2²³ = 975799313 is a prime.

It is not a weakly prime, because it can be changed into another prime (984187961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 492093960 + 492093961.

It is an arithmetic number, because the mean of its divisors is an integer number (492093961).

Almost surely, 2^984187921 is an apocalyptic number.

It is an amenable number.

984187921 is a deficient number, since it is larger than the sum of its proper divisors (1).

984187921 is an equidigital number, since it uses as much as digits as its factorization.

984187921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 49.

The square root of 984187921 is about 31371.7694910568. The cubic root of 984187921 is about 994.7012801577.

The spelling of 984187921 in words is "nine hundred eighty-four million, one hundred eighty-seven thousand, nine hundred twenty-one".