21155153513501 has 16 divisors (see below), whose sum is σ = 24555714355200. Its totient is φ = 17849578610160.

The previous prime is 21155153513479. The next prime is 21155153513509. The reversal of 21155153513501 is 10531535155112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21155153513501 is a prime.

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, 15465005 + ... + 16777266.

It is an arithmetic number, because the mean of its divisors is an integer number (1534732147200).

Almost surely, 2^{21155153513501} is an apocalyptic number.

It is an amenable number.

21155153513501 is a deficient number, since it is larger than the sum of its proper divisors (3400560841699).

21155153513501 is a wasteful number, since it uses less digits than its factorization.

21155153513501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32243744.

The product of its (nonzero) digits is 56250, while the sum is 38.

Adding to 21155153513501 its reverse (10531535155112), we get a palindrome (31686688668613).

The spelling of 21155153513501 in words is "twenty-one trillion, one hundred fifty-five billion, one hundred fifty-three million, five hundred thirteen thousand, five hundred one".