646637770 has 16 divisors (see below), whose sum is σ = 1181321568. Its totient is φ = 254794320.

The previous prime is 646637767. The next prime is 646637779. The reversal of 646637770 is 77736646.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 646637770.

It is not an unprimeable number, because it can be changed into a prime (646637779) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 481896 + ... + 483235.

It is an arithmetic number, because the mean of its divisors is an integer number (73832598).

Almost surely, 2^646637770 is an apocalyptic number.

646637770 is a deficient number, since it is larger than the sum of its proper divisors (534683798).

646637770 is a wasteful number, since it uses less digits than its factorization.

646637770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 965205.

The product of its (nonzero) digits is 889056, while the sum is 46.

The square root of 646637770 is about 25429.0733216922. The cubic root of 646637770 is about 864.7429354065.

The spelling of 646637770 in words is "six hundred forty-six million, six hundred thirty-seven thousand, seven hundred seventy".