1989736957 has 4 divisors (see below), whose sum is σ = 2142793660. Its totient is φ = 1836680256.

The previous prime is 1989736949. The next prime is 1989736997. The reversal of 1989736957 is 7596379891.

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

It can be written as a sum of positive squares in 2 ways, for example, as 997864921 + 991872036 = 31589^2 + 31494^2 .

It is a cyclic number.

It is not a de Polignac number, because 1989736957 - 2³ = 1989736949 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 (1989736927) 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, 76528332 + ... + 76528357.

It is an arithmetic number, because the mean of its divisors is an integer number (535698415).

Almost surely, 2^1989736957 is an apocalyptic number.

It is an amenable number.

1989736957 is a deficient number, since it is larger than the sum of its proper divisors (153056703).

1989736957 is a wasteful number, since it uses less digits than its factorization.

1989736957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153056702.

The product of its digits is 25719120, while the sum is 64.

The square root of 1989736957 is about 44606.4676588497. The cubic root of 1989736957 is about 1257.7622490436.

The spelling of 1989736957 in words is "one billion, nine hundred eighty-nine million, seven hundred thirty-six thousand, nine hundred fifty-seven".