21040255515 has 16 divisors (see below), whose sum is σ = 33726648096. Its totient is φ = 11200723200.

The previous prime is 21040255507. The next prime is 21040255531. The reversal of 21040255515 is 51555204012.

It is not a de Polignac number, because 21040255515 - 2³ = 21040255507 is a prime.

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, 1288266 + ... + 1304495.

It is an arithmetic number, because the mean of its divisors is an integer number (2107915506).

Almost surely, 2^21040255515 is an apocalyptic number.

21040255515 is a deficient number, since it is larger than the sum of its proper divisors (12686392581).

21040255515 is a wasteful number, since it uses less digits than its factorization.

21040255515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2593310.

The product of its (nonzero) digits is 10000, while the sum is 30.

Adding to 21040255515 its reverse (51555204012), we get a palindrome (72595459527).

The spelling of 21040255515 in words is "twenty-one billion, forty million, two hundred fifty-five thousand, five hundred fifteen".