1989397831 has 4 divisors (see below), whose sum is σ = 2094103000. Its totient is φ = 1884692664.

The previous prime is 1989397801. The next prime is 1989397841. The reversal of 1989397831 is 1387939891.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1989397831 - 2⁵ = 1989397799 is a prime.

It is a super-2 number, since 2×1989397831² = 7915407459975009122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989397801) 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, 52352556 + ... + 52352593.

It is an arithmetic number, because the mean of its divisors is an integer number (523525750).

Almost surely, 2^1989397831 is an apocalyptic number.

1989397831 is a deficient number, since it is larger than the sum of its proper divisors (104705169).

1989397831 is a wasteful number, since it uses less digits than its factorization.

1989397831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104705168.

The product of its digits is 2939328, while the sum is 58.

The square root of 1989397831 is about 44602.6661871238. Note that the first 3 decimals coincide. The cubic root of 1989397831 is about 1257.6907883221.

The spelling of 1989397831 in words is "one billion, nine hundred eighty-nine million, three hundred ninety-seven thousand, eight hundred thirty-one".