64771921 has 8 divisors (see below), whose sum is σ = 68652360. Its totient is φ = 60899328.

The previous prime is 64771919. The next prime is 64771937. The reversal of 64771921 is 12917746.

It can be written as a sum of positive squares in 4 ways, for example, as 28302400 + 36469521 = 5320^2 + 6039^2 .

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 64771921 - 2¹ = 64771919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64771901) 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, 31105 + ... + 33121.

It is an arithmetic number, because the mean of its divisors is an integer number (8581545).

Almost surely, 2^64771921 is an apocalyptic number.

It is an amenable number.

64771921 is a deficient number, since it is larger than the sum of its proper divisors (3880439).

64771921 is a wasteful number, since it uses less digits than its factorization.

64771921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3923.

The product of its digits is 21168, while the sum is 37.

The square root of 64771921 is about 8048.1004591146. The cubic root of 64771921 is about 401.6017462114.

The spelling of 64771921 in words is "sixty-four million, seven hundred seventy-one thousand, nine hundred twenty-one".