138897817 has 4 divisors (see below), whose sum is σ = 139163920. Its totient is φ = 138631716.

The previous prime is 138897799. The next prime is 138897823. The reversal of 138897817 is 718798831.

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.

It is a cyclic number.

It is not a de Polignac number, because 138897817 - 2¹⁵ = 138865049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138897827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132267 + ... + 133312.

It is an arithmetic number, because the mean of its divisors is an integer number (34790980).

Almost surely, 2^138897817 is an apocalyptic number.

It is an amenable number.

138897817 is a deficient number, since it is larger than the sum of its proper divisors (266103).

138897817 is an equidigital number, since it uses as much as digits as its factorization.

138897817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266102.

The product of its digits is 677376, while the sum is 52.

The square root of 138897817 is about 11785.4918013632. The cubic root of 138897817 is about 517.8831807747.

The spelling of 138897817 in words is "one hundred thirty-eight million, eight hundred ninety-seven thousand, eight hundred seventeen".