646220397 has 16 divisors (see below), whose sum is σ = 913834368. Its totient is φ = 405324480.

The previous prime is 646220387. The next prime is 646220411. The reversal of 646220397 is 793022646.

It is not a de Polignac number, because 646220397 - 2¹⁹ = 645696109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646220317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72558 + ... + 80975.

It is an arithmetic number, because the mean of its divisors is an integer number (57114648).

Almost surely, 2^646220397 is an apocalyptic number.

It is an amenable number.

646220397 is a deficient number, since it is larger than the sum of its proper divisors (267613971).

646220397 is a wasteful number, since it uses less digits than its factorization.

646220397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153620.

The product of its (nonzero) digits is 108864, while the sum is 39.

The square root of 646220397 is about 25420.8653865284. The cubic root of 646220397 is about 864.5568456306.

The spelling of 646220397 in words is "six hundred forty-six million, two hundred twenty thousand, three hundred ninety-seven".