137991989 has 2 divisors, whose sum is σ = 137991990. Its totient is φ = 137991988.

The previous prime is 137991983. The next prime is 137992027. The reversal of 137991989 is 989199731.

137991989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133217764 + 4774225 = 11542^2 + 2185^2 .

It is a cyclic number.

It is not a de Polignac number, because 137991989 - 2¹² = 137987893 is a prime.

It is a super-2 number, since 2×137991989² = 38083578056352242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (137991983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68995994 + 68995995.

It is an arithmetic number, because the mean of its divisors is an integer number (68995995).

Almost surely, 2^137991989 is an apocalyptic number.

It is an amenable number.

137991989 is a deficient number, since it is larger than the sum of its proper divisors (1).

137991989 is an equidigital number, since it uses as much as digits as its factorization.

137991989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1102248, while the sum is 56.

The square root of 137991989 is about 11746.9991487188. Note that the first 3 decimals coincide. The cubic root of 137991989 is about 516.7549255167.

The spelling of 137991989 in words is "one hundred thirty-seven million, nine hundred ninety-one thousand, nine hundred eighty-nine".