21545320215051 has 12 divisors (see below), whose sum is σ = 31121233845312. Its totient is φ = 14363447229936.

The previous prime is 21545320215043. The next prime is 21545320215071. The reversal of 21545320215051 is 15051202354512.

21545320215051 is a `hidden beast` number, since 2 + 1 + 5 + 4 + 532 + 0 + 21 + 50 + 51 = 666.

It is not a de Polignac number, because 21545320215051 - 2³ = 21545320215043 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21545320214997 and 21545320215015.

It is not an unprimeable number, because it can be changed into a prime (21545320215031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6915931 + ... + 9535236.

It is an arithmetic number, because the mean of its divisors is an integer number (2593436153776).

Almost surely, 2^{21545320215051} is an apocalyptic number.

21545320215051 is a deficient number, since it is larger than the sum of its proper divisors (9575913630261).

21545320215051 is a wasteful number, since it uses less digits than its factorization.

21545320215051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16596690 (or 16596687 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 36.

Adding to 21545320215051 its reverse (15051202354512), we get a palindrome (36596522569563).

The spelling of 21545320215051 in words is "twenty-one trillion, five hundred forty-five billion, three hundred twenty million, two hundred fifteen thousand, fifty-one".