648956821 has 8 divisors (see below), whose sum is σ = 670477824. Its totient is φ = 627472560.

The previous prime is 648956813. The next prime is 648956843. The reversal of 648956821 is 128659846.

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 648956821 - 2³ = 648956813 is a prime.

It is a super-2 number, since 2×648956821² = 842289911044852082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648956621) 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, 29355 + ... + 46471.

It is an arithmetic number, because the mean of its divisors is an integer number (83809728).

Almost surely, 2^648956821 is an apocalyptic number.

It is an amenable number.

648956821 is a deficient number, since it is larger than the sum of its proper divisors (21521003).

648956821 is a wasteful number, since it uses less digits than its factorization.

648956821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18371.

The product of its digits is 829440, while the sum is 49.

The square root of 648956821 is about 25474.6309296131. The cubic root of 648956821 is about 865.7754508327.

The spelling of 648956821 in words is "six hundred forty-eight million, nine hundred fifty-six thousand, eight hundred twenty-one".