1989544979 has 4 divisors (see below), whose sum is σ = 1989923376. Its totient is φ = 1989166584.

The previous prime is 1989544957. The next prime is 1989545023. The reversal of 1989544979 is 9794459891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1989544979 is a prime.

It is a super-2 number, since 2×1989544979² = 7916578446928220882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1989544379) 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, 181199 + ... + 191864.

It is an arithmetic number, because the mean of its divisors is an integer number (497480844).

Almost surely, 2^1989544979 is an apocalyptic number.

1989544979 is a deficient number, since it is larger than the sum of its proper divisors (378397).

1989544979 is an equidigital number, since it uses as much as digits as its factorization.

1989544979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378396.

The product of its digits is 29393280, while the sum is 65.

The square root of 1989544979 is about 44604.3156992684. The cubic root of 1989544979 is about 1257.7217963853.

The spelling of 1989544979 in words is "one billion, nine hundred eighty-nine million, five hundred forty-four thousand, nine hundred seventy-nine".