64721345 has 8 divisors (see below), whose sum is σ = 83639976. Its totient is φ = 47794176.

The previous prime is 64721341. The next prime is 64721357. The reversal of 64721345 is 54312746.

It can be written as a sum of positive squares in 4 ways, for example, as 1168561 + 63552784 = 1081^2 + 7972^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 64721345 - 2² = 64721341 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64721341) 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, 497792 + ... + 497921.

It is an arithmetic number, because the mean of its divisors is an integer number (10454997).

Almost surely, 2^64721345 is an apocalyptic number.

64721345 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

64721345 is a deficient number, since it is larger than the sum of its proper divisors (18918631).

64721345 is a wasteful number, since it uses less digits than its factorization.

64721345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995731.

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

The square root of 64721345 is about 8044.9577376143. The cubic root of 64721345 is about 401.4971911382.

The spelling of 64721345 in words is "sixty-four million, seven hundred twenty-one thousand, three hundred forty-five".