646837490 has 16 divisors (see below), whose sum is σ = 1253869848. Its totient is φ = 238832256.

The previous prime is 646837447. The next prime is 646837507. The reversal of 646837490 is 94738646.

It is a Cunningham number, because it is equal to 25433²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 480091921 + 166745569 = 21911^2 + 12913^2 .

It is a super-3 number, since 3×646837490³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2487707 + ... + 2487966.

Almost surely, 2^646837490 is an apocalyptic number.

646837490 is a deficient number, since it is larger than the sum of its proper divisors (607032358).

646837490 is a wasteful number, since it uses less digits than its factorization.

646837490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4975693.

The product of its (nonzero) digits is 870912, while the sum is 47.

The square root of 646837490 is about 25433.0000196595. Note that the first 4 decimals coincide. The cubic root of 646837490 is about 864.8319541686.

The spelling of 646837490 in words is "six hundred forty-six million, eight hundred thirty-seven thousand, four hundred ninety".