1678297989 has 4 divisors (see below), whose sum is σ = 2237730656. Its totient is φ = 1118865324.

The previous prime is 1678297981. The next prime is 1678297993. The reversal of 1678297989 is 9897928761.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1678297989 - 2³ = 1678297981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1678297981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 279716329 + ... + 279716334.

It is an arithmetic number, because the mean of its divisors is an integer number (559432664).

Almost surely, 2^1678297989 is an apocalyptic number.

It is an amenable number.

1678297989 is a deficient number, since it is larger than the sum of its proper divisors (559432667).

1678297989 is an equidigital number, since it uses as much as digits as its factorization.

1678297989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559432666.

The product of its digits is 27433728, while the sum is 66.

The square root of 1678297989 is about 40967.0353943265. The cubic root of 1678297989 is about 1188.3828017090.

The spelling of 1678297989 in words is "one billion, six hundred seventy-eight million, two hundred ninety-seven thousand, nine hundred eighty-nine".