21255426505 has 16 divisors (see below), whose sum is σ = 25564089600. Its totient is φ = 16966002240.

The previous prime is 21255426503. The next prime is 21255426509. The reversal of 21255426505 is 50562455212.

It is not a de Polignac number, because 21255426505 - 2¹ = 21255426503 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21255426503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6659460 + ... + 6662650.

It is an arithmetic number, because the mean of its divisors is an integer number (1597755600).

Almost surely, 2^21255426505 is an apocalyptic number.

It is an amenable number.

21255426505 is a deficient number, since it is larger than the sum of its proper divisors (4308663095).

21255426505 is a wasteful number, since it uses less digits than its factorization.

21255426505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5784.

The product of its (nonzero) digits is 120000, while the sum is 37.

The spelling of 21255426505 in words is "twenty-one billion, two hundred fifty-five million, four hundred twenty-six thousand, five hundred five".