646981193 has 4 divisors (see below), whose sum is σ = 647429760. Its totient is φ = 646532628.

The previous prime is 646981183. The next prime is 646981219. The reversal of 646981193 is 391189646.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 646981193 - 2²⁸ = 378545737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646981133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222113 + ... + 225006.

It is an arithmetic number, because the mean of its divisors is an integer number (161857440).

Almost surely, 2^646981193 is an apocalyptic number.

It is an amenable number.

646981193 is a deficient number, since it is larger than the sum of its proper divisors (448567).

646981193 is a wasteful number, since it uses less digits than its factorization.

646981193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448566.

The product of its digits is 279936, while the sum is 47.

The square root of 646981193 is about 25435.8249915351. The cubic root of 646981193 is about 864.8959938211.

The spelling of 646981193 in words is "six hundred forty-six million, nine hundred eighty-one thousand, one hundred ninety-three".