67887721 has 4 divisors (see below), whose sum is σ = 74059344. Its totient is φ = 61716100.

The previous prime is 67887713. The next prime is 67887731. The reversal of 67887721 is 12778876.

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 67887721 - 2³ = 67887713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67887731) 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, 3085795 + ... + 3085816.

It is an arithmetic number, because the mean of its divisors is an integer number (18514836).

Almost surely, 2^67887721 is an apocalyptic number.

It is an amenable number.

67887721 is a deficient number, since it is larger than the sum of its proper divisors (6171623).

67887721 is a wasteful number, since it uses less digits than its factorization.

67887721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6171622.

The product of its digits is 263424, while the sum is 46.

The square root of 67887721 is about 8239.4005243100. The cubic root of 67887721 is about 407.9407373395.

It can be divided in two parts, 67 and 887721, that added together give a palindrome (887788).

The spelling of 67887721 in words is "sixty-seven million, eight hundred eighty-seven thousand, seven hundred twenty-one".