648570904921 has 3 divisors (see below), whose sum is σ = 648571710261. Its totient is φ = 648570099582.

The previous prime is 648570904907. The next prime is 648570904939. The reversal of 648570904921 is 129409075846.

The square root of 648570904921 is 805339.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 648570904921 - 2⁵ = 648570904889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (648570904981) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 402670 + ... + 1208008.

It is an arithmetic number, because the mean of its divisors is an integer number (216190570087).

Almost surely, 2^648570904921 is an apocalyptic number.

648570904921 is the 805339-th square number.

648570904921 is the 402670-th centered octagonal number.

It is an amenable number.

648570904921 is a deficient number, since it is larger than the sum of its proper divisors (805340).

648570904921 is an frugal number, since it uses more digits than its factorization.

648570904921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1610678 (or 805339 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 55.

The spelling of 648570904921 in words is "six hundred forty-eight billion, five hundred seventy million, nine hundred four thousand, nine hundred twenty-one".