67449721 has 4 divisors (see below), whose sum is σ = 67526992. Its totient is φ = 67372452.

The previous prime is 67449691. The next prime is 67449749. The reversal of 67449721 is 12794476.

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 67449721 - 2⁵ = 67449689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67449121) 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, 37311 + ... + 39076.

It is an arithmetic number, because the mean of its divisors is an integer number (16881748).

Almost surely, 2^67449721 is an apocalyptic number.

It is an amenable number.

67449721 is a deficient number, since it is larger than the sum of its proper divisors (77271).

67449721 is an equidigital number, since it uses as much as digits as its factorization.

67449721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77270.

The product of its digits is 84672, while the sum is 40.

The square root of 67449721 is about 8212.7779100619. Note that the first 3 decimals coincide. The cubic root of 67449721 is about 407.0615224124.

The spelling of 67449721 in words is "sixty-seven million, four hundred forty-nine thousand, seven hundred twenty-one".