64109721 has 8 divisors (see below), whose sum is σ = 92055040. Its totient is φ = 39452112.

The previous prime is 64109707. The next prime is 64109741. The reversal of 64109721 is 12790146.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 64109721 - 2⁷ = 64109593 is a prime.

It is a super-2 number, since 2×64109721² = 8220112653395682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64109741) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 821881 + ... + 821958.

It is an arithmetic number, because the mean of its divisors is an integer number (11506880).

Almost surely, 2^64109721 is an apocalyptic number.

It is an amenable number.

64109721 is a deficient number, since it is larger than the sum of its proper divisors (27945319).

64109721 is a wasteful number, since it uses less digits than its factorization.

64109721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1643855.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 64109721 is about 8006.8546258815. The cubic root of 64109721 is about 400.2284549127.

Adding to 64109721 its reverse (12790146), we get a palindrome (76899867).

The spelling of 64109721 in words is "sixty-four million, one hundred nine thousand, seven hundred twenty-one".