21155112253 has 8 divisors (see below), whose sum is σ = 23079572640. Its totient is φ = 19230863280.

The previous prime is 21155112133. The next prime is 21155112269. The reversal of 21155112253 is 35221155112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21155112253 - 2³³ = 12565177661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155112283) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 215758 + ... + 298096.

It is an arithmetic number, because the mean of its divisors is an integer number (2884946580).

Almost surely, 2^21155112253 is an apocalyptic number.

It is an amenable number.

21155112253 is a deficient number, since it is larger than the sum of its proper divisors (1924460387).

21155112253 is a wasteful number, since it uses less digits than its factorization.

21155112253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105707.

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

Adding to 21155112253 its reverse (35221155112), we get a palindrome (56376267365).

The spelling of 21155112253 in words is "twenty-one billion, one hundred fifty-five million, one hundred twelve thousand, two hundred fifty-three".