21231554353502 has 8 divisors (see below), whose sum is σ = 31855918042200. Its totient is φ = 10612915006104.

The previous prime is 21231554353417. The next prime is 21231554353571. The reversal of 21231554353502 is 20535345513212.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21231554353502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1431076052 + ... + 1431090887.

It is an arithmetic number, because the mean of its divisors is an integer number (3981989755275).

Almost surely, 2^{21231554353502} is an apocalyptic number.

21231554353502 is a deficient number, since it is larger than the sum of its proper divisors (10624363688698).

21231554353502 is a wasteful number, since it uses less digits than its factorization.

21231554353502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2862170650.

The product of its (nonzero) digits is 540000, while the sum is 41.

Adding to 21231554353502 its reverse (20535345513212), we get a palindrome (41766899866714).

The spelling of 21231554353502 in words is "twenty-one trillion, two hundred thirty-one billion, five hundred fifty-four million, three hundred fifty-three thousand, five hundred two".