21209553224 has 32 divisors (see below), whose sum is σ = 41523736320. Its totient is φ = 10137152256.

The previous prime is 21209553223. The next prime is 21209553283. The reversal of 21209553224 is 42235590212.

It is a Cunningham number, because it is equal to 145635²-1.

It is not an unprimeable number, because it can be changed into a prime (21209553223) 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, 254864 + ... + 327680.

It is an arithmetic number, because the mean of its divisors is an integer number (1297616760).

Almost surely, 2^21209553224 is an apocalyptic number.

It is an amenable number.

21209553224 is a deficient number, since it is larger than the sum of its proper divisors (20314183096).

21209553224 is a wasteful number, since it uses less digits than its factorization.

21209553224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74429 (or 74425 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 35.

The spelling of 21209553224 in words is "twenty-one billion, two hundred nine million, five hundred fifty-three thousand, two hundred twenty-four".