21661450133 has 8 divisors (see below), whose sum is σ = 22937271552. Its totient is φ = 20385808576.

The previous prime is 21661450093. The next prime is 21661450199. The reversal of 21661450133 is 33105416612.

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

It is a cyclic number.

It is not a de Polignac number, because 21661450133 - 2⁸ = 21661449877 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 21661450133.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661450033) 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, 263516 + ... + 335802.

It is an arithmetic number, because the mean of its divisors is an integer number (2867158944).

Almost surely, 2^21661450133 is an apocalyptic number.

It is an amenable number.

21661450133 is a deficient number, since it is larger than the sum of its proper divisors (1275821419).

21661450133 is a wasteful number, since it uses less digits than its factorization.

21661450133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89931.

The product of its (nonzero) digits is 12960, while the sum is 32.

Adding to 21661450133 its reverse (33105416612), we get a palindrome (54766866745).

The spelling of 21661450133 in words is "twenty-one billion, six hundred sixty-one million, four hundred fifty thousand, one hundred thirty-three".