1989423997 has 8 divisors (see below), whose sum is σ = 2297944512. Its totient is φ = 1702180800.

The previous prime is 1989423979. The next prime is 1989424001. The reversal of 1989423997 is 7993249891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1989423997 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 (1989423797) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5319129 + ... + 5319502.

It is an arithmetic number, because the mean of its divisors is an integer number (287243064).

Almost surely, 2^1989423997 is an apocalyptic number.

1989423997 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1989423997 is a deficient number, since it is larger than the sum of its proper divisors (308520515).

1989423997 is a wasteful number, since it uses less digits than its factorization.

1989423997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10638659.

The product of its digits is 8817984, while the sum is 61.

The square root of 1989423997 is about 44602.9595094317. The cubic root of 1989423997 is about 1257.6963023177.

The spelling of 1989423997 in words is "one billion, nine hundred eighty-nine million, four hundred twenty-three thousand, nine hundred ninety-seven".