21154550305 has 32 divisors (see below), whose sum is σ = 29657041920. Its totient is φ = 14184015360.

The previous prime is 21154550171. The next prime is 21154550309. The reversal of 21154550305 is 50305545112.

It is not a de Polignac number, because 21154550305 - 2¹³ = 21154542113 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21154550309) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1937301 + ... + 1948189.

It is an arithmetic number, because the mean of its divisors is an integer number (926782560).

Almost surely, 2^21154550305 is an apocalyptic number.

It is an amenable number.

21154550305 is a deficient number, since it is larger than the sum of its proper divisors (8502491615).

21154550305 is a wasteful number, since it uses less digits than its factorization.

21154550305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12129.

The product of its (nonzero) digits is 15000, while the sum is 31.

The spelling of 21154550305 in words is "twenty-one billion, one hundred fifty-four million, five hundred fifty thousand, three hundred five".