21121143551 has 8 divisors (see below), whose sum is σ = 21573273024. Its totient is φ = 20669128480.

The previous prime is 21121143517. The next prime is 21121143557. The reversal of 21121143551 is 15534112112.

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 21121143551 - 2⁶ = 21121143487 is a prime.

It is a super-2 number, since 2×21121143551² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21121143551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121143557) 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, 418541 + ... + 466281.

It is an arithmetic number, because the mean of its divisors is an integer number (2696659128).

Almost surely, 2^21121143551 is an apocalyptic number.

21121143551 is a deficient number, since it is larger than the sum of its proper divisors (452129473).

21121143551 is an equidigital number, since it uses as much as digits as its factorization.

21121143551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57201.

The product of its digits is 1200, while the sum is 26.

Adding to 21121143551 its reverse (15534112112), we get a palindrome (36655255663).

The spelling of 21121143551 in words is "twenty-one billion, one hundred twenty-one million, one hundred forty-three thousand, five hundred fifty-one".