64125721 has 8 divisors (see below), whose sum is σ = 70020000. Its totient is φ = 58242240.

The previous prime is 64125697. The next prime is 64125749. The reversal of 64125721 is 12752146.

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 64125721 - 2⁵ = 64125689 is a prime.

It is a super-2 number, since 2×64125721² = 8224216187539682, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64125721.

It is not an unprimeable number, because it can be changed into a prime (64125781) 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, 14545 + ... + 18433.

It is an arithmetic number, because the mean of its divisors is an integer number (8752500).

Almost surely, 2^64125721 is an apocalyptic number.

It is an amenable number.

64125721 is a deficient number, since it is larger than the sum of its proper divisors (5894279).

64125721 is a wasteful number, since it uses less digits than its factorization.

64125721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5399.

The product of its digits is 3360, while the sum is 28.

The square root of 64125721 is about 8007.8537074550. The cubic root of 64125721 is about 400.2617474333.

Adding to 64125721 its reverse (12752146), we get a palindrome (76877867).

It can be divided in two parts, 641257 and 21, that added together give a triangular number (641278 = T₁₁₃₂).

The spelling of 64125721 in words is "sixty-four million, one hundred twenty-five thousand, seven hundred twenty-one".