67391678621 has 4 divisors (see below), whose sum is σ = 67535986752. Its totient is φ = 67247370492.

The previous prime is 67391678611. The next prime is 67391678657. The reversal of 67391678621 is 12687619376.

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 a de Polignac number, because none of the positive numbers 2^k-67391678621 is a prime.

It is a super-2 number, since 2×67391678621² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67391678611) 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, 72153365 + ... + 72154298.

It is an arithmetic number, because the mean of its divisors is an integer number (16883996688).

Almost surely, 2^67391678621 is an apocalyptic number.

It is an amenable number.

67391678621 is a deficient number, since it is larger than the sum of its proper divisors (144308131).

67391678621 is a wasteful number, since it uses less digits than its factorization.

67391678621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144308130.

The product of its digits is 4572288, while the sum is 56.

The spelling of 67391678621 in words is "sixty-seven billion, three hundred ninety-one million, six hundred seventy-eight thousand, six hundred twenty-one".