21003328649 has 8 divisors (see below), whose sum is σ = 21238943880. Its totient is φ = 20768256000.

The previous prime is 21003328627. The next prime is 21003328729. The reversal of 21003328649 is 94682330012.

It can be written as a sum of positive squares in 4 ways, for example, as 7893078649 + 13110250000 = 88843^2 + 114500^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21003328649 is a prime.

It is a super-2 number, since 2×21003328649² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21003328949) 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, 57542 + ... + 212879.

It is an arithmetic number, because the mean of its divisors is an integer number (2654867985).

Almost surely, 2^21003328649 is an apocalyptic number.

It is an amenable number.

21003328649 is a deficient number, since it is larger than the sum of its proper divisors (235615231).

21003328649 is a wasteful number, since it uses less digits than its factorization.

21003328649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271291.

The product of its (nonzero) digits is 62208, while the sum is 38.

The spelling of 21003328649 in words is "twenty-one billion, three million, three hundred twenty-eight thousand, six hundred forty-nine".