67500721 has 4 divisors (see below), whose sum is σ = 67878000. Its totient is φ = 67123444.

The previous prime is 67500701. The next prime is 67500739. The reversal of 67500721 is 12700576.

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-67500721 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 67500721.

It is not an unprimeable number, because it can be changed into a prime (67500701) 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, 188371 + ... + 188728.

It is an arithmetic number, because the mean of its divisors is an integer number (16969500).

Almost surely, 2^67500721 is an apocalyptic number.

It is an amenable number.

67500721 is a deficient number, since it is larger than the sum of its proper divisors (377279).

67500721 is a wasteful number, since it uses less digits than its factorization.

67500721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 377278.

The product of its (nonzero) digits is 2940, while the sum is 28.

The square root of 67500721 is about 8215.8822411230. The cubic root of 67500721 is about 407.1640921841.

The spelling of 67500721 in words is "sixty-seven million, five hundred thousand, seven hundred twenty-one".