65128021 has 8 divisors (see below), whose sum is σ = 74525184. Its totient is φ = 55754160.

The previous prime is 65128009. The next prime is 65128027. The reversal of 65128021 is 12082156.

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

It is not a de Polignac number, because 65128021 - 2⁵ = 65127989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65128027) 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, 651 + ... + 11431.

It is an arithmetic number, because the mean of its divisors is an integer number (9315648).

Almost surely, 2^65128021 is an apocalyptic number.

It is an amenable number.

65128021 is a deficient number, since it is larger than the sum of its proper divisors (9397163).

65128021 is a wasteful number, since it uses less digits than its factorization.

65128021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11651.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 65128021 is about 8070.1933681914. The cubic root of 65128021 is about 402.3363706114.

The spelling of 65128021 in words is "sixty-five million, one hundred twenty-eight thousand, twenty-one".