21255211153 has 4 divisors (see below), whose sum is σ = 23187503088. Its totient is φ = 19322919220.

The previous prime is 21255211151. The next prime is 21255211157. The reversal of 21255211153 is 35111255212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21255211153 - 2¹ = 21255211151 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21255211151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 966145951 + ... + 966145972.

It is an arithmetic number, because the mean of its divisors is an integer number (5796875772).

Almost surely, 2^21255211153 is an apocalyptic number.

It is an amenable number.

21255211153 is a deficient number, since it is larger than the sum of its proper divisors (1932291935).

21255211153 is a wasteful number, since it uses less digits than its factorization.

21255211153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1932291934.

The product of its digits is 3000, while the sum is 28.

Adding to 21255211153 its reverse (35111255212), we get a palindrome (56366466365).

The spelling of 21255211153 in words is "twenty-one billion, two hundred fifty-five million, two hundred eleven thousand, one hundred fifty-three".