138443857 has 4 divisors (see below), whose sum is σ = 139023360. Its totient is φ = 137864356.

The previous prime is 138443807. The next prime is 138443863. The reversal of 138443857 is 758344831.

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 138443857 - 2¹⁵ = 138411089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138443807) 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, 289393 + ... + 289870.

It is an arithmetic number, because the mean of its divisors is an integer number (34755840).

Almost surely, 2^138443857 is an apocalyptic number.

It is an amenable number.

138443857 is a deficient number, since it is larger than the sum of its proper divisors (579503).

138443857 is an equidigital number, since it uses as much as digits as its factorization.

138443857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579502.

The product of its digits is 322560, while the sum is 43.

The square root of 138443857 is about 11766.2167666587. The cubic root of 138443857 is about 517.3183654692.

The spelling of 138443857 in words is "one hundred thirty-eight million, four hundred forty-three thousand, eight hundred fifty-seven".