67139221 has 4 divisors (see below), whose sum is σ = 67186944. Its totient is φ = 67091500.

The previous prime is 67139213. The next prime is 67139243. The reversal of 67139221 is 12293176.

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 67139221 - 2³ = 67139213 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67139291) 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, 21685 + ... + 24586.

It is an arithmetic number, because the mean of its divisors is an integer number (16796736).

Almost surely, 2^67139221 is an apocalyptic number.

It is an amenable number.

67139221 is a deficient number, since it is larger than the sum of its proper divisors (47723).

67139221 is a wasteful number, since it uses less digits than its factorization.

67139221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47722.

The product of its digits is 4536, while the sum is 31.

The square root of 67139221 is about 8193.8526347500. The cubic root of 67139221 is about 406.4359352104.

The spelling of 67139221 in words is "sixty-seven million, one hundred thirty-nine thousand, two hundred twenty-one".