648872781 has 16 divisors (see below), whose sum is σ = 918767040. Its totient is φ = 406183680.

The previous prime is 648872773. The next prime is 648872789. The reversal of 648872781 is 187278846.

It is an interprime number because it is at equal distance from previous prime (648872773) and next prime (648872789).

It is not a de Polignac number, because 648872781 - 2³ = 648872773 is a prime.

It is a super-2 number, since 2×648872781² = 842071771845347922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648872789) 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, 43930 + ... + 56811.

It is an arithmetic number, because the mean of its divisors is an integer number (57422940).

Almost surely, 2^648872781 is an apocalyptic number.

It is an amenable number.

648872781 is a deficient number, since it is larger than the sum of its proper divisors (269894259).

648872781 is a wasteful number, since it uses less digits than its factorization.

648872781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100876.

The product of its digits is 1204224, while the sum is 51.

The square root of 648872781 is about 25472.9813920554. The cubic root of 648872781 is about 865.7380765383.

The spelling of 648872781 in words is "six hundred forty-eight million, eight hundred seventy-two thousand, seven hundred eighty-one".