648841721 has 8 divisors (see below), whose sum is σ = 722888064. Its totient is φ = 577305520.

The previous prime is 648841709. The next prime is 648841747. The reversal of 648841721 is 127148846.

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

It is not a de Polignac number, because 648841721 - 2²² = 644647417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (648841021) 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, 626990 + ... + 628023.

It is an arithmetic number, because the mean of its divisors is an integer number (90361008).

Almost surely, 2^648841721 is an apocalyptic number.

It is an amenable number.

648841721 is a deficient number, since it is larger than the sum of its proper divisors (74046343).

648841721 is a wasteful number, since it uses less digits than its factorization.

648841721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1255071.

The product of its digits is 86016, while the sum is 41.

The square root of 648841721 is about 25472.3717191784. The cubic root of 648841721 is about 865.7242627089.

The spelling of 648841721 in words is "six hundred forty-eight million, eight hundred forty-one thousand, seven hundred twenty-one".