21963906649 has 16 divisors (see below), whose sum is σ = 23449305600. Its totient is φ = 20526041536.

The previous prime is 21963906611. The next prime is 21963906707. The reversal of 21963906649 is 94660936912.

It is a cyclic number.

It is not a de Polignac number, because 21963906649 - 2¹⁷ = 21963775577 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21963906649.

It is not an unprimeable number, because it can be changed into a prime (21963906049) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 253647 + ... + 329035.

It is an arithmetic number, because the mean of its divisors is an integer number (1465581600).

Almost surely, 2^21963906649 is an apocalyptic number.

It is an amenable number.

21963906649 is a deficient number, since it is larger than the sum of its proper divisors (1485398951).

21963906649 is a wasteful number, since it uses less digits than its factorization.

21963906649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75704.

The product of its (nonzero) digits is 3779136, while the sum is 55.

The spelling of 21963906649 in words is "twenty-one billion, nine hundred sixty-three million, nine hundred six thousand, six hundred forty-nine".