21355555145 has 8 divisors (see below), whose sum is σ = 25647627456. Its totient is φ = 17070469936.

The previous prime is 21355555139. The next prime is 21355555147. The reversal of 21355555145 is 54155555312.

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 21355555145 - 2¹⁴ = 21355538761 is a prime.

It is a super-2 number, since 2×21355555145² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21355555147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1740047 + ... + 1752276.

It is an arithmetic number, because the mean of its divisors is an integer number (3205953432).

Almost surely, 2^21355555145 is an apocalyptic number.

It is an amenable number.

21355555145 is a deficient number, since it is larger than the sum of its proper divisors (4292072311).

21355555145 is a wasteful number, since it uses less digits than its factorization.

21355555145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3493551.

The product of its digits is 375000, while the sum is 41.

The spelling of 21355555145 in words is "twenty-one billion, three hundred fifty-five million, five hundred fifty-five thousand, one hundred forty-five".