21554091 has 36 divisors (see below), whose sum is σ = 34714368. Its totient is φ = 12871872.

The previous prime is 21554081. The next prime is 21554111. The reversal of 21554091 is 19045512.

21554091 is a `hidden beast` number, since 21 + 554 + 0 + 91 = 666.

It is not a de Polignac number, because 21554091 - 2¹¹ = 21552043 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21554041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 56086 + ... + 56468.

It is an arithmetic number, because the mean of its divisors is an integer number (964288).

Almost surely, 2^21554091 is an apocalyptic number.

21554091 is a deficient number, since it is larger than the sum of its proper divisors (13160277).

21554091 is a wasteful number, since it uses less digits than its factorization.

21554091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452 (or 436 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 21554091 is about 4642.6383662741. The cubic root of 21554091 is about 278.2978838602.

The spelling of 21554091 in words is "twenty-one million, five hundred fifty-four thousand, ninety-one".