646738126 has 4 divisors (see below), whose sum is σ = 970107192. Its totient is φ = 323369062.

The previous prime is 646738121. The next prime is 646738129. The reversal of 646738126 is 621837646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 621837646 = 2 ⋅310918823.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646738121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161684530 + ... + 161684533.

It is an arithmetic number, because the mean of its divisors is an integer number (242526798).

Almost surely, 2^646738126 is an apocalyptic number.

646738126 is a deficient number, since it is larger than the sum of its proper divisors (323369066).

646738126 is a wasteful number, since it uses less digits than its factorization.

646738126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323369065.

The product of its digits is 290304, while the sum is 43.

The square root of 646738126 is about 25431.0464983256. The cubic root of 646738126 is about 864.7876681544.

The spelling of 646738126 in words is "six hundred forty-six million, seven hundred thirty-eight thousand, one hundred twenty-six".