647514821 has 4 divisors (see below), whose sum is σ = 647574444. Its totient is φ = 647455200.

The previous prime is 647514809. The next prime is 647514869. The reversal of 647514821 is 128415746.

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, and also an emirpimes, since its reverse is a distinct semiprime: 128415746 = 2 ⋅64207873.

It can be written as a sum of positive squares in 2 ways, for example, as 829921 + 646684900 = 911^2 + 25430^2 .

It is a cyclic number.

It is not a de Polignac number, because 647514821 - 2²⁶ = 580405957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647504821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8390 + ... + 36951.

It is an arithmetic number, because the mean of its divisors is an integer number (161893611).

Almost surely, 2^647514821 is an apocalyptic number.

It is an amenable number.

647514821 is a deficient number, since it is larger than the sum of its proper divisors (59623).

647514821 is a wasteful number, since it uses less digits than its factorization.

647514821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59622.

The product of its digits is 53760, while the sum is 38.

The square root of 647514821 is about 25446.3125226426. The cubic root of 647514821 is about 865.1337162836.

The spelling of 647514821 in words is "six hundred forty-seven million, five hundred fourteen thousand, eight hundred twenty-one".