21512534340155 has 8 divisors (see below), whose sum is σ = 26168671910112. Its totient is φ = 16974273670848.

The previous prime is 21512534340151. The next prime is 21512534340223. The reversal of 21512534340155 is 55104343521512.

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

It is a cyclic number.

It is not a de Polignac number, because 21512534340155 - 2² = 21512534340151 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21512534340151) 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, 29469224759 + ... + 29469225488.

It is an arithmetic number, because the mean of its divisors is an integer number (3271083988764).

Almost surely, 2^{21512534340155} is an apocalyptic number.

21512534340155 is a deficient number, since it is larger than the sum of its proper divisors (4656137569957).

21512534340155 is an equidigital number, since it uses as much as digits as its factorization.

21512534340155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58938450325.

The product of its (nonzero) digits is 360000, while the sum is 41.

Adding to 21512534340155 its reverse (55104343521512), we get a palindrome (76616877861667).

The spelling of 21512534340155 in words is "twenty-one trillion, five hundred twelve billion, five hundred thirty-four million, three hundred forty thousand, one hundred fifty-five".