646643137 has 16 divisors (see below), whose sum is σ = 775065600. Its totient is φ = 527476752.

The previous prime is 646643099. The next prime is 646643141. The reversal of 646643137 is 731346646.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 646643137 - 2¹¹ = 646641089 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 646643137.

It is not an unprimeable number, because it can be changed into a prime (646643147) 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, 21948 + ... + 42130.

It is an arithmetic number, because the mean of its divisors is an integer number (48441600).

Almost surely, 2^646643137 is an apocalyptic number.

It is an amenable number.

646643137 is a deficient number, since it is larger than the sum of its proper divisors (128422463).

646643137 is a wasteful number, since it uses less digits than its factorization.

646643137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20412.

The product of its digits is 217728, while the sum is 40.

The square root of 646643137 is about 25429.1788502893. The cubic root of 646643137 is about 864.7453278137.

The spelling of 646643137 in words is "six hundred forty-six million, six hundred forty-three thousand, one hundred thirty-seven".