646738159 has 4 divisors (see below), whose sum is σ = 650311480. Its totient is φ = 643164840.

The previous prime is 646738129. The next prime is 646738177. The reversal of 646738159 is 951837646.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646738159 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646738109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1786389 + ... + 1786750.

It is an arithmetic number, because the mean of its divisors is an integer number (162577870).

Almost surely, 2^646738159 is an apocalyptic number.

646738159 is a deficient number, since it is larger than the sum of its proper divisors (3573321).

646738159 is a wasteful number, since it uses less digits than its factorization.

646738159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3573320.

The product of its digits is 1088640, while the sum is 49.

The square root of 646738159 is about 25431.0471471389. The cubic root of 646738159 is about 864.7876828631.

The spelling of 646738159 in words is "six hundred forty-six million, seven hundred thirty-eight thousand, one hundred fifty-nine".