21145917255 has 8 divisors (see below), whose sum is σ = 33833467632. Its totient is φ = 11277822528.

The previous prime is 21145917197. The next prime is 21145917271. The reversal of 21145917255 is 55271954112.

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

It is not a de Polignac number, because 21145917255 - 2¹³ = 21145909063 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 704863894 + ... + 704863923.

It is an arithmetic number, because the mean of its divisors is an integer number (4229183454).

Almost surely, 2^21145917255 is an apocalyptic number.

21145917255 is a deficient number, since it is larger than the sum of its proper divisors (12687550377).

21145917255 is a wasteful number, since it uses less digits than its factorization.

21145917255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1409727825.

The product of its digits is 126000, while the sum is 42.

The spelling of 21145917255 in words is "twenty-one billion, one hundred forty-five million, nine hundred seventeen thousand, two hundred fifty-five".