646406426 has 4 divisors (see below), whose sum is σ = 969609642. Its totient is φ = 323203212.

The previous prime is 646406417. The next prime is 646406461. The reversal of 646406426 is 624604646.

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

It can be written as a sum of positive squares in only one way, i.e., 614990401 + 31416025 = 24799^2 + 5605^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 646406426.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 161601605 + ... + 161601608.

Almost surely, 2^646406426 is an apocalyptic number.

646406426 is a deficient number, since it is larger than the sum of its proper divisors (323203216).

646406426 is a wasteful number, since it uses less digits than its factorization.

646406426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323203215.

The product of its (nonzero) digits is 165888, while the sum is 38.

The square root of 646406426 is about 25424.5241056740. The cubic root of 646406426 is about 864.6397983485.

The spelling of 646406426 in words is "six hundred forty-six million, four hundred six thousand, four hundred twenty-six".