21568891449 has 8 divisors (see below), whose sum is σ = 32866882240. Its totient is φ = 12325080816.

The previous prime is 21568891427. The next prime is 21568891453. The reversal of 21568891449 is 94419886512.

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

It is not a de Polignac number, because 21568891449 - 2⁵ = 21568891417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21568891469) 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, 513545014 + ... + 513545055.

It is an arithmetic number, because the mean of its divisors is an integer number (4108360280).

Almost surely, 2^21568891449 is an apocalyptic number.

It is an amenable number.

21568891449 is a deficient number, since it is larger than the sum of its proper divisors (11297990791).

21568891449 is a wasteful number, since it uses less digits than its factorization.

21568891449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1027090079.

The product of its digits is 4976640, while the sum is 57.

The spelling of 21568891449 in words is "twenty-one billion, five hundred sixty-eight million, eight hundred ninety-one thousand, four hundred forty-nine".