21125553245 has 16 divisors (see below), whose sum is σ = 26886529152. Its totient is φ = 15900624960.

The previous prime is 21125553209. The next prime is 21125553259. The reversal of 21125553245 is 54235552112.

It is a happy number.

It is not a de Polignac number, because 21125553245 - 2⁶ = 21125553181 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 1498727 + ... + 1512756.

It is an arithmetic number, because the mean of its divisors is an integer number (1680408072).

Almost surely, 2^21125553245 is an apocalyptic number.

It is an amenable number.

21125553245 is a deficient number, since it is larger than the sum of its proper divisors (5760975907).

21125553245 is a wasteful number, since it uses less digits than its factorization.

21125553245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3011572.

The product of its digits is 60000, while the sum is 35.

The spelling of 21125553245 in words is "twenty-one billion, one hundred twenty-five million, five hundred fifty-three thousand, two hundred forty-five".