64453721 has 4 divisors (see below), whose sum is σ = 64499712. Its totient is φ = 64407732.

The previous prime is 64453693. The next prime is 64453723. The reversal of 64453721 is 12735446.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12735446 = 2 ⋅6367723.

It is a cyclic number.

It is not a de Polignac number, because 64453721 - 2¹⁸ = 64191577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64453723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20825 + ... + 23718.

It is an arithmetic number, because the mean of its divisors is an integer number (16124928).

Almost surely, 2^64453721 is an apocalyptic number.

It is an amenable number.

64453721 is a deficient number, since it is larger than the sum of its proper divisors (45991).

64453721 is a wasteful number, since it uses less digits than its factorization.

64453721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45990.

The product of its digits is 20160, while the sum is 32.

The square root of 64453721 is about 8028.3074804096. The cubic root of 64453721 is about 400.9430270860.

The spelling of 64453721 in words is "sixty-four million, four hundred fifty-three thousand, seven hundred twenty-one".