21153121055 has 8 divisors (see below), whose sum is σ = 27691358544. Its totient is φ = 15384088000.

The previous prime is 21153121051. The next prime is 21153121081. The reversal of 21153121055 is 55012135112.

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

It is not a de Polignac number, because 21153121055 - 2² = 21153121051 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 (21153121051) 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, 192301046 + ... + 192301155.

It is an arithmetic number, because the mean of its divisors is an integer number (3461419818).

Almost surely, 2^21153121055 is an apocalyptic number.

21153121055 is a deficient number, since it is larger than the sum of its proper divisors (6538237489).

21153121055 is a wasteful number, since it uses less digits than its factorization.

21153121055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384602217.

The product of its (nonzero) digits is 1500, while the sum is 26.

Adding to 21153121055 its reverse (55012135112), we get a palindrome (76165256167).

The spelling of 21153121055 in words is "twenty-one billion, one hundred fifty-three million, one hundred twenty-one thousand, fifty-five".