646481381381 has 8 divisors (see below), whose sum is σ = 735915564864. Its totient is φ = 562157722720.

The previous prime is 646481381363. The next prime is 646481381417. The reversal of 646481381381 is 183183184646.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 646481381381 - 2²² = 646477187077 is a prime.

It is a super-2 number, since 2×646481381381² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646481381311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1277630936 + ... + 1277631441.

It is an arithmetic number, because the mean of its divisors is an integer number (91989445608).

Almost surely, 2^646481381381 is an apocalyptic number.

It is an amenable number.

646481381381 is a deficient number, since it is larger than the sum of its proper divisors (89434183483).

646481381381 is a wasteful number, since it uses less digits than its factorization.

646481381381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2555262411.

The product of its digits is 2654208, while the sum is 53.

The spelling of 646481381381 in words is "six hundred forty-six billion, four hundred eighty-one million, three hundred eighty-one thousand, three hundred eighty-one".