646627749 has 16 divisors (see below), whose sum is σ = 868707840. Its totient is φ = 427826880.

The previous prime is 646627733. The next prime is 646627757. The reversal of 646627749 is 947726646.

It is not a de Polignac number, because 646627749 - 2⁴ = 646627733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646622749) 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, 366732 + ... + 368490.

It is an arithmetic number, because the mean of its divisors is an integer number (54294240).

Almost surely, 2^646627749 is an apocalyptic number.

It is an amenable number.

646627749 is a deficient number, since it is larger than the sum of its proper divisors (222080091).

646627749 is a wasteful number, since it uses less digits than its factorization.

646627749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2620.

The product of its digits is 3048192, while the sum is 51.

The square root of 646627749 is about 25428.8762826830. The cubic root of 646627749 is about 864.7384683854.

The spelling of 646627749 in words is "six hundred forty-six million, six hundred twenty-seven thousand, seven hundred forty-nine".