84651768821 has 4 divisors (see below), whose sum is σ = 89631284652. Its totient is φ = 79672252992.

The previous prime is 84651768797. The next prime is 84651768833. The reversal of 84651768821 is 12886715648.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36754257796 + 47897511025 = 191714^2 + 218855^2 .

It is a cyclic number.

It is not a de Polignac number, because 84651768821 - 2¹⁸ = 84651506677 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 (84651168821) 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, 2489757890 + ... + 2489757923.

It is an arithmetic number, because the mean of its divisors is an integer number (22407821163).

Almost surely, 2^84651768821 is an apocalyptic number.

It is an amenable number.

84651768821 is a deficient number, since it is larger than the sum of its proper divisors (4979515831).

84651768821 is a wasteful number, since it uses less digits than its factorization.

84651768821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4979515830.

The product of its digits is 5160960, while the sum is 56.

The spelling of 84651768821 in words is "eighty-four billion, six hundred fifty-one million, seven hundred sixty-eight thousand, eight hundred twenty-one".