67940021 has 4 divisors (see below), whose sum is σ = 68161632. Its totient is φ = 67718412.

The previous prime is 67940009. The next prime is 67940057. The reversal of 67940021 is 12004976.

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 67940021 - 2¹⁸ = 67677877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (67940221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110345 + ... + 110958.

It is an arithmetic number, because the mean of its divisors is an integer number (17040408).

Almost surely, 2^67940021 is an apocalyptic number.

It is an amenable number.

67940021 is a deficient number, since it is larger than the sum of its proper divisors (221611).

67940021 is a wasteful number, since it uses less digits than its factorization.

67940021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221610.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 67940021 is about 8242.5736878720. The cubic root of 67940021 is about 408.0454682283.

Adding to 67940021 its reverse (12004976), we get a palindrome (79944997).

The spelling of 67940021 in words is "sixty-seven million, nine hundred forty thousand, twenty-one".