21545001115 has 16 divisors (see below), whose sum is σ = 28736526816. Its totient is φ = 15373446400.

The previous prime is 21545001109. The next prime is 21545001133. The reversal of 21545001115 is 51110054512.

It is not a de Polignac number, because 21545001115 - 2⁵ = 21545001083 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21545001115.

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, 3692626 + ... + 3698455.

It is an arithmetic number, because the mean of its divisors is an integer number (1796032926).

Almost surely, 2^21545001115 is an apocalyptic number.

21545001115 is a deficient number, since it is larger than the sum of its proper divisors (7191525701).

21545001115 is a wasteful number, since it uses less digits than its factorization.

21545001115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7391150.

The product of its (nonzero) digits is 1000, while the sum is 25.

Adding to 21545001115 its reverse (51110054512), we get a palindrome (72655055627).

The spelling of 21545001115 in words is "twenty-one billion, five hundred forty-five million, one thousand, one hundred fifteen".