139497989 has 2 divisors, whose sum is σ = 139497990. Its totient is φ = 139497988.

The previous prime is 139497973. The next prime is 139497991. The reversal of 139497989 is 989794931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128640964 + 10857025 = 11342^2 + 3295^2 .

It is a cyclic number.

It is not a de Polignac number, because 139497989 - 2⁴ = 139497973 is a prime.

Together with 139497991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139497959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69748994 + 69748995.

It is an arithmetic number, because the mean of its divisors is an integer number (69748995).

Almost surely, 2^139497989 is an apocalyptic number.

It is an amenable number.

139497989 is a deficient number, since it is larger than the sum of its proper divisors (1).

139497989 is an equidigital number, since it uses as much as digits as its factorization.

139497989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4408992, while the sum is 59.

The square root of 139497989 is about 11810.9266782924. The cubic root of 139497989 is about 518.6280265992.

The spelling of 139497989 in words is "one hundred thirty-nine million, four hundred ninety-seven thousand, nine hundred eighty-nine".