64721497 has 4 divisors (see below), whose sum is σ = 64797876. Its totient is φ = 64645120.

The previous prime is 64721483. The next prime is 64721509. The reversal of 64721497 is 79412746.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 51609856 + 13111641 = 7184^2 + 3621^2 .

It is a cyclic number.

It is not a de Polignac number, because 64721497 - 2⁷ = 64721369 is a prime.

It is a super-3 number, since 3×64721497³ (a number of 24 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64721477) 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, 36904 + ... + 38617.

It is an arithmetic number, because the mean of its divisors is an integer number (16199469).

Almost surely, 2^64721497 is an apocalyptic number.

It is an amenable number.

64721497 is a deficient number, since it is larger than the sum of its proper divisors (76379).

64721497 is an equidigital number, since it uses as much as digits as its factorization.

64721497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76378.

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

The square root of 64721497 is about 8044.9671845198. The cubic root of 64721497 is about 401.4975054474.

The spelling of 64721497 in words is "sixty-four million, seven hundred twenty-one thousand, four hundred ninety-seven".