21355555144 has 48 divisors (see below), whose sum is σ = 50813552880. Its totient is φ = 8320344480.

The previous prime is 21355555139. The next prime is 21355555147. The reversal of 21355555144 is 44155555312.

It is a junction number, because it is equal to n+sod(n) for n = 21355555097 and 21355555106.

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

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2471982 + ... + 2480605.

It is an arithmetic number, because the mean of its divisors is an integer number (1058615685).

Almost surely, 2^21355555144 is an apocalyptic number.

It is an amenable number.

21355555144 is an abundant number, since it is smaller than the sum of its proper divisors (29457997736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21355555144 is a wasteful number, since it uses less digits than its factorization.

21355555144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4952618 (or 4952607 counting only the distinct ones).

The product of its digits is 300000, while the sum is 40.

The spelling of 21355555144 in words is "twenty-one billion, three hundred fifty-five million, five hundred fifty-five thousand, one hundred forty-four".