648508181 has 4 divisors (see below), whose sum is σ = 648576000. Its totient is φ = 648440364.

The previous prime is 648508123. The next prime is 648508199. The reversal of 648508181 is 181805846.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 648508181 - 2¹⁰ = 648507157 is a prime.

It is a super-2 number, since 2×648508181² = 841125721647857522, 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 (648508781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16631 + ... + 39668.

It is an arithmetic number, because the mean of its divisors is an integer number (162144000).

Almost surely, 2^648508181 is an apocalyptic number.

It is an amenable number.

648508181 is a deficient number, since it is larger than the sum of its proper divisors (67819).

648508181 is a wasteful number, since it uses less digits than its factorization.

648508181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67818.

The product of its (nonzero) digits is 61440, while the sum is 41.

The square root of 648508181 is about 25465.8237840444. The cubic root of 648508181 is about 865.5758941347.

The spelling of 648508181 in words is "six hundred forty-eight million, five hundred eight thousand, one hundred eighty-one".