21551244153 has 4 divisors (see below), whose sum is σ = 28734992208. Its totient is φ = 14367496100.

The previous prime is 21551244137. The next prime is 21551244157. The reversal of 21551244153 is 35144215512.

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 a cyclic number.

It is not a de Polignac number, because 21551244153 - 2⁴ = 21551244137 is a prime.

It is a super-2 number, since 2×21551244153² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21551244157) 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 3 ways as a sum of consecutive naturals, for example, 3591874023 + ... + 3591874028.

It is an arithmetic number, because the mean of its divisors is an integer number (7183748052).

Almost surely, 2^21551244153 is an apocalyptic number.

It is an amenable number.

21551244153 is a deficient number, since it is larger than the sum of its proper divisors (7183748055).

21551244153 is an equidigital number, since it uses as much as digits as its factorization.

21551244153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7183748054.

The product of its digits is 24000, while the sum is 33.

Adding to 21551244153 its reverse (35144215512), we get a palindrome (56695459665).

The spelling of 21551244153 in words is "twenty-one billion, five hundred fifty-one million, two hundred forty-four thousand, one hundred fifty-three".