21554013 has 16 divisors (see below), whose sum is σ = 32296320. Its totient is φ = 12686784.

The previous prime is 21553997. The next prime is 21554033. The reversal of 21554013 is 31045512.

It is not a de Polignac number, because 21554013 - 2⁴ = 21553997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554033) 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 15 ways as a sum of consecutive naturals, for example, 11118 + ... + 12911.

It is an arithmetic number, because the mean of its divisors is an integer number (2018520).

Almost surely, 2^21554013 is an apocalyptic number.

21554013 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21554013 is a deficient number, since it is larger than the sum of its proper divisors (10742307).

21554013 is a wasteful number, since it uses less digits than its factorization.

21554013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24068.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 21554013 is about 4642.6299658706. The cubic root of 21554013 is about 278.2975481581.

Adding to 21554013 its reverse (31045512), we get a palindrome (52599525).

The spelling of 21554013 in words is "twenty-one million, five hundred fifty-four thousand, thirteen".