21515411543055 has 32 divisors (see below), whose sum is σ = 36101892326400. Its totient is φ = 10920822359040.

The previous prime is 21515411542997. The next prime is 21515411543069. The reversal of 21515411543055 is 55034511451512.

It is not a de Polignac number, because 21515411543055 - 2²⁷ = 21515277325327 is a prime.

It is a super-2 number, since 2×21515411543055² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21515411542998 and 21515411543016.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 156623586 + ... + 156760895.

It is an arithmetic number, because the mean of its divisors is an integer number (1128184135200).

Almost surely, 2^{21515411543055} is an apocalyptic number.

21515411543055 is a deficient number, since it is larger than the sum of its proper divisors (14586480783345).

21515411543055 is a wasteful number, since it uses less digits than its factorization.

21515411543055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313384711.

The product of its (nonzero) digits is 300000, while the sum is 42.

Adding to 21515411543055 its reverse (55034511451512), we get a palindrome (76549922994567).

The spelling of 21515411543055 in words is "twenty-one trillion, five hundred fifteen billion, four hundred eleven million, five hundred forty-three thousand, fifty-five".