21511545215351 has 8 divisors (see below), whose sum is σ = 22266420582000. Its totient is φ = 20757543045120.

The previous prime is 21511545215311. The next prime is 21511545215371. The reversal of 21511545215351 is 15351254511512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21511545215351 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21511545215299 and 21511545215308.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21511545215311) 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, 218248970 + ... + 218347511.

It is an arithmetic number, because the mean of its divisors is an integer number (2783302572750).

Almost surely, 2^{21511545215351} is an apocalyptic number.

21511545215351 is a deficient number, since it is larger than the sum of its proper divisors (754875366649).

21511545215351 is a wasteful number, since it uses less digits than its factorization.

21511545215351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436598209.

The product of its digits is 150000, while the sum is 41.

Adding to 21511545215351 its reverse (15351254511512), we get a palindrome (36862799726863).

The spelling of 21511545215351 in words is "twenty-one trillion, five hundred eleven billion, five hundred forty-five million, two hundred fifteen thousand, three hundred fifty-one".