64844869781 has 16 divisors (see below), whose sum is σ = 65563014720. Its totient is φ = 64131471360.

The previous prime is 64844869709. The next prime is 64844869811. The reversal of 64844869781 is 18796844846.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64844869781 is a prime.

It is a super-2 number, since 2×64844869781² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64844829781) 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, 46021205 + ... + 46022613.

It is an arithmetic number, because the mean of its divisors is an integer number (4097688420).

Almost surely, 2^64844869781 is an apocalyptic number.

It is an amenable number.

64844869781 is a deficient number, since it is larger than the sum of its proper divisors (718144939).

64844869781 is a wasteful number, since it uses less digits than its factorization.

64844869781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2756.

The product of its digits is 74317824, while the sum is 65.

The spelling of 64844869781 in words is "sixty-four billion, eight hundred forty-four million, eight hundred sixty-nine thousand, seven hundred eighty-one".