21554355321 has 6 divisors (see below), whose sum is σ = 31134068810. Its totient is φ = 14369570208.

The previous prime is 21554355313. The next prime is 21554355337. The reversal of 21554355321 is 12355345512.

21554355321 is a `hidden beast` number, since 2 + 1 + 554 + 35 + 53 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11715897600 + 9838457721 = 108240^2 + 99189^2 .

It is not a de Polignac number, because 21554355321 - 2³ = 21554355313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21554351321) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1197464176 + ... + 1197464193.

Almost surely, 2^21554355321 is an apocalyptic number.

It is an amenable number.

21554355321 is a deficient number, since it is larger than the sum of its proper divisors (9579713489).

21554355321 is a wasteful number, since it uses less digits than its factorization.

21554355321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2394928375 (or 2394928372 counting only the distinct ones).

The product of its digits is 90000, while the sum is 36.

The spelling of 21554355321 in words is "twenty-one billion, five hundred fifty-four million, three hundred fifty-five thousand, three hundred twenty-one".