64877721 has 8 divisors (see below), whose sum is σ = 86605344. Its totient is φ = 43200960.

The previous prime is 64877713. The next prime is 64877731. The reversal of 64877721 is 12777846.

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

It is not a de Polignac number, because 64877721 - 2³ = 64877713 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (64877711) 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 7 ways as a sum of consecutive naturals, for example, 9631 + ... + 14916.

It is an arithmetic number, because the mean of its divisors is an integer number (10825668).

Almost surely, 2^64877721 is an apocalyptic number.

It is an amenable number.

64877721 is a deficient number, since it is larger than the sum of its proper divisors (21727623).

64877721 is a wasteful number, since it uses less digits than its factorization.

64877721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25431.

The product of its digits is 131712, while the sum is 42.

The square root of 64877721 is about 8054.6707567721. The cubic root of 64877721 is about 401.8202892191.

The spelling of 64877721 in words is "sixty-four million, eight hundred seventy-seven thousand, seven hundred twenty-one".