21517485355 has 16 divisors (see below), whose sum is σ = 25904450880. Its totient is φ = 17158407552.

The previous prime is 21517485349. The next prime is 21517485373. The reversal of 21517485355 is 55358471512.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21517485355 is a prime.

It is a super-3 number, since 3×21517485355³ (a number of 32 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3663361 + ... + 3669229.

It is an arithmetic number, because the mean of its divisors is an integer number (1619028180).

Almost surely, 2^21517485355 is an apocalyptic number.

21517485355 is a deficient number, since it is larger than the sum of its proper divisors (4386965525).

21517485355 is a wasteful number, since it uses less digits than its factorization.

21517485355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8118.

The product of its digits is 840000, while the sum is 46.

The spelling of 21517485355 in words is "twenty-one billion, five hundred seventeen million, four hundred eighty-five thousand, three hundred fifty-five".