67721213 has 4 divisors (see below), whose sum is σ = 77395680. Its totient is φ = 58046748.

The previous prime is 67721197. The next prime is 67721231. The reversal of 67721213 is 31212776.

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 67721213 - 2⁴ = 67721197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67721233) 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, 4837223 + ... + 4837236.

It is an arithmetic number, because the mean of its divisors is an integer number (19348920).

Almost surely, 2^67721213 is an apocalyptic number.

It is an amenable number.

67721213 is a deficient number, since it is larger than the sum of its proper divisors (9674467).

67721213 is an equidigital number, since it uses as much as digits as its factorization.

67721213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9674466.

The product of its digits is 3528, while the sum is 29.

The square root of 67721213 is about 8229.2899450682. The cubic root of 67721213 is about 407.6069459726.

Adding to 67721213 its reverse (31212776), we get a palindrome (98933989).

The spelling of 67721213 in words is "sixty-seven million, seven hundred twenty-one thousand, two hundred thirteen".