21515343555555 has 24 divisors (see below), whose sum is σ = 37293427281552. Its totient is φ = 11474799090624.

The previous prime is 21515343555553. The next prime is 21515343555557. The reversal of 21515343555555 is 55555534351512.

21515343555555 is a `hidden beast` number, since 2 + 1 + 5 + 1 + 5 + 3 + 4 + 35 + 55 + 555 = 666.

It is an interprime number because it is at equal distance from previous prime (21515343555553) and next prime (21515343555557).

It is not a de Polignac number, because 21515343555555 - 2¹ = 21515343555553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21515343555553) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10638552 + ... + 12498378.

It is an arithmetic number, because the mean of its divisors is an integer number (1553892803398).

Almost surely, 2^{21515343555555} is an apocalyptic number.

21515343555555 is a deficient number, since it is larger than the sum of its proper divisors (15778083725997).

21515343555555 is a wasteful number, since it uses less digits than its factorization.

21515343555555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2116915 (or 2116912 counting only the distinct ones).

The product of its digits is 28125000, while the sum is 54.

The spelling of 21515343555555 in words is "twenty-one trillion, five hundred fifteen billion, three hundred forty-three million, five hundred fifty-five thousand, five hundred fifty-five".