21155153513500 has 48 divisors (see below), whose sum is σ = 46204026496992. Its totient is φ = 8461846896000.

The previous prime is 21155153513479. The next prime is 21155153513509. The reversal of 21155153513500 is 531535155112.

It is a self number, because there is not a number n which added to its sum of digits gives 21155153513500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155153513509) 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, 19992735 + ... + 21024265.

It is an arithmetic number, because the mean of its divisors is an integer number (962583885354).

Almost surely, 2^{21155153513500} is an apocalyptic number.

21155153513500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155153513500 is an abundant number, since it is smaller than the sum of its proper divisors (25048872983492).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21155153513500 is a wasteful number, since it uses less digits than its factorization.

21155153513500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072567 (or 1072555 counting only the distinct ones).

The product of its (nonzero) digits is 56250, while the sum is 37.

Adding to 21155153513500 its reverse (531535155112), we get a palindrome (21686688668612).

The spelling of 21155153513500 in words is "twenty-one trillion, one hundred fifty-five billion, one hundred fifty-three million, five hundred thirteen thousand, five hundred".