646378467681 has 16 divisors (see below), whose sum is σ = 867977339328. Its totient is φ = 427858200000.

The previous prime is 646378467659. The next prime is 646378467701. The reversal of 646378467681 is 186764873646.

646378467681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 646378467681 - 2¹¹ = 646378465633 is a prime.

It is a super-2 number, since 2×646378467681² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (646378467281) 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, 823570 + ... + 1403931.

It is an arithmetic number, because the mean of its divisors is an integer number (54248583708).

Almost surely, 2^646378467681 is an apocalyptic number.

It is an amenable number.

646378467681 is a deficient number, since it is larger than the sum of its proper divisors (221598871647).

646378467681 is a wasteful number, since it uses less digits than its factorization.

646378467681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2228192.

The product of its digits is 195084288, while the sum is 66.

The spelling of 646378467681 in words is "six hundred forty-six billion, three hundred seventy-eight million, four hundred sixty-seven thousand, six hundred eighty-one".