64128021 has 8 divisors (see below), whose sum is σ = 90004320. Its totient is φ = 40501872.

The previous prime is 64128017. The next prime is 64128047. The reversal of 64128021 is 12082146.

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

It is not a de Polignac number, because 64128021 - 2² = 64128017 is a prime.

It is a super-2 number, since 2×64128021² = 8224806154752882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 64127982 and 64128000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64128121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 562470 + ... + 562583.

It is an arithmetic number, because the mean of its divisors is an integer number (11250540).

Almost surely, 2^64128021 is an apocalyptic number.

It is an amenable number.

64128021 is a deficient number, since it is larger than the sum of its proper divisors (25876299).

64128021 is a wasteful number, since it uses less digits than its factorization.

64128021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1125075.

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 64128021 is about 8007.9973151844. The cubic root of 64128021 is about 400.2665327779.

The spelling of 64128021 in words is "sixty-four million, one hundred twenty-eight thousand, twenty-one".