21554329 has 4 divisors (see below), whose sum is σ = 21589120. Its totient is φ = 21519540.

The previous prime is 21554311. The next prime is 21554359. The reversal of 21554329 is 92345512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21554329 - 2⁵ = 21554297 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21554329.

It is not an unprimeable number, because it can be changed into a prime (21554359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16449 + ... + 17710.

It is an arithmetic number, because the mean of its divisors is an integer number (5397280).

Almost surely, 2^21554329 is an apocalyptic number.

It is an amenable number.

21554329 is a deficient number, since it is larger than the sum of its proper divisors (34791).

21554329 is an equidigital number, since it uses as much as digits as its factorization.

21554329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34790.

The product of its digits is 10800, while the sum is 31.

The square root of 21554329 is about 4642.6639981804. The cubic root of 21554329 is about 278.2989081770.

The spelling of 21554329 in words is "twenty-one million, five hundred fifty-four thousand, three hundred twenty-nine".