138487969 has 4 divisors (see below), whose sum is σ = 138766000. Its totient is φ = 138209940.

The previous prime is 138487961. The next prime is 138487997. The reversal of 138487969 is 969784831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 969784831 = 53 ⋅18297827.

It is a cyclic number.

It is not a de Polignac number, because 138487969 - 2³ = 138487961 is a prime.

It is a super-2 number, since 2×138487969² = 38357835115489922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138487961) 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, 138267 + ... + 139264.

It is an arithmetic number, because the mean of its divisors is an integer number (34691500).

Almost surely, 2^138487969 is an apocalyptic number.

It is an amenable number.

138487969 is a deficient number, since it is larger than the sum of its proper divisors (278031).

138487969 is an equidigital number, since it uses as much as digits as its factorization.

138487969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278030.

The product of its digits is 2612736, while the sum is 55.

The square root of 138487969 is about 11768.0911366287. The cubic root of 138487969 is about 517.3733035622.

The spelling of 138487969 in words is "one hundred thirty-eight million, four hundred eighty-seven thousand, nine hundred sixty-nine".