648921 has 16 divisors (see below), whose sum is σ = 1065344. Its totient is φ = 342144.

The previous prime is 648917. The next prime is 648931. The reversal of 648921 is 129846.

648921 = T₇₁ + T₇₂ + ... + T₁₆₁.

648921 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 648921 - 2² = 648917 is a prime.

648921 is strictly pandigital in base 7.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 648921.

It is not an unprimeable number, because it can be changed into a prime (648911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 916 + ... + 1461.

It is an arithmetic number, because the mean of its divisors is an integer number (66584).

2⁶⁴⁸⁹²¹ is an apocalyptic number.

It is an amenable number.

648921 is a deficient number, since it is larger than the sum of its proper divisors (416423).

648921 is a wasteful number, since it uses less digits than its factorization.

648921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2400.

The product of its digits is 3456, while the sum is 30.

The square root of 648921 is about 805.5563295015. The cubic root of 648921 is about 86.5759520901.

The spelling of 648921 in words is "six hundred forty-eight thousand, nine hundred twenty-one".