649999022221 has 4 divisors (see below), whose sum is σ = 652217449212. Its totient is φ = 647780595232.

The previous prime is 649999022213. The next prime is 649999022273. The reversal of 649999022221 is 122220999946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122220999946 = 2 ⋅61110499973.

It can be written as a sum of positive squares in 2 ways, for example, as 545662916100 + 104336106121 = 738690^2 + 323011^2 .

It is a cyclic number.

It is not a de Polignac number, because 649999022221 - 2³ = 649999022213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649999052221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1109213056 + ... + 1109213641.

It is an arithmetic number, because the mean of its divisors is an integer number (163054362303).

Almost surely, 2^649999022221 is an apocalyptic number.

It is an amenable number.

649999022221 is a deficient number, since it is larger than the sum of its proper divisors (2218426991).

649999022221 is a wasteful number, since it uses less digits than its factorization.

649999022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2218426990.

The product of its (nonzero) digits is 2519424, while the sum is 55.

The spelling of 649999022221 in words is "six hundred forty-nine billion, nine hundred ninety-nine million, twenty-two thousand, two hundred twenty-one".