648716781 has 8 divisors (see below), whose sum is σ = 865872864. Its totient is φ = 432019280.

The previous prime is 648716773. The next prime is 648716797. The reversal of 648716781 is 187617846.

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 648716781 - 2³ = 648716773 is a prime.

It is a super-2 number, since 2×648716781² = 841666923902003922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 648716781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648716581) 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, 111330 + ... + 117011.

It is an arithmetic number, because the mean of its divisors is an integer number (108234108).

Almost surely, 2^648716781 is an apocalyptic number.

It is an amenable number.

648716781 is a deficient number, since it is larger than the sum of its proper divisors (217156083).

648716781 is a wasteful number, since it uses less digits than its factorization.

648716781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229291.

The product of its digits is 451584, while the sum is 48.

The square root of 648716781 is about 25469.9191400365. The cubic root of 648716781 is about 865.6686916149.

The spelling of 648716781 in words is "six hundred forty-eight million, seven hundred sixteen thousand, seven hundred eighty-one".