1649609218 has 4 divisors (see below), whose sum is σ = 2474413830. Its totient is φ = 824804608.

The previous prime is 1649609207. The next prime is 1649609219. The reversal of 1649609218 is 8129069461.

It is a happy number.

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., 1584597249 + 65011969 = 39807^2 + 8063^2 .

It is a super-2 number, since 2×1649609218² = 5442421144221143048, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1649609219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 412402303 + ... + 412402306.

Almost surely, 2^1649609218 is an apocalyptic number.

1649609218 is a deficient number, since it is larger than the sum of its proper divisors (824804612).

1649609218 is an equidigital number, since it uses as much as digits as its factorization.

1649609218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 824804611.

The product of its (nonzero) digits is 186624, while the sum is 46.

The square root of 1649609218 is about 40615.3815444346. The cubic root of 1649609218 is about 1181.5724554846.

The spelling of 1649609218 in words is "one billion, six hundred forty-nine million, six hundred nine thousand, two hundred eighteen".