64256721 has 8 divisors (see below), whose sum is σ = 88630080. Its totient is φ = 41360592.

The previous prime is 64256711. The next prime is 64256737. The reversal of 64256721 is 12765246.

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

It is not a de Polignac number, because 64256721 - 2⁷ = 64256593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64256711) 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, 369205 + ... + 369378.

It is an arithmetic number, because the mean of its divisors is an integer number (11078760).

Almost surely, 2^64256721 is an apocalyptic number.

It is an amenable number.

64256721 is a deficient number, since it is larger than the sum of its proper divisors (24373359).

64256721 is a wasteful number, since it uses less digits than its factorization.

64256721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 738615.

The product of its digits is 20160, while the sum is 33.

The square root of 64256721 is about 8016.0290044385. The cubic root of 64256721 is about 400.5341218837.

The spelling of 64256721 in words is "sixty-four million, two hundred fifty-six thousand, seven hundred twenty-one".