138213949 has 4 divisors (see below), whose sum is σ = 139555936. Its totient is φ = 136871964.

The previous prime is 138213947. The next prime is 138213967. The reversal of 138213949 is 949312831.

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: 949312831 = 21521 ⋅44111.

It is a cyclic number.

It is not a de Polignac number, because 138213949 - 2¹ = 138213947 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138213941) 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, 670839 + ... + 671044.

It is an arithmetic number, because the mean of its divisors is an integer number (34888984).

Almost surely, 2^138213949 is an apocalyptic number.

It is an amenable number.

138213949 is a deficient number, since it is larger than the sum of its proper divisors (1341987).

138213949 is a wasteful number, since it uses less digits than its factorization.

138213949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1341986.

The product of its digits is 46656, while the sum is 40.

The square root of 138213949 is about 11756.4428718894. The cubic root of 138213949 is about 517.0318437187.

The spelling of 138213949 in words is "one hundred thirty-eight million, two hundred thirteen thousand, nine hundred forty-nine".