21554047 has 8 divisors (see below), whose sum is σ = 22418640. Its totient is φ = 20697600.

The previous prime is 21554041. The next prime is 21554063. The reversal of 21554047 is 74045512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21554047 - 2⁷ = 21553919 is a prime.

It is a Duffinian number.

It is a congruent number.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3672 + ... + 7522.

It is an arithmetic number, because the mean of its divisors is an integer number (2802330).

Almost surely, 2^21554047 is an apocalyptic number.

21554047 is a deficient number, since it is larger than the sum of its proper divisors (864593).

21554047 is a wasteful number, since it uses less digits than its factorization.

21554047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4073.

The product of its (nonzero) digits is 5600, while the sum is 28.

The square root of 21554047 is about 4642.6336275868. The cubic root of 21554047 is about 278.2976944899.

Adding to 21554047 its reverse (74045512), we get a palindrome (95599559).

The spelling of 21554047 in words is "twenty-one million, five hundred fifty-four thousand, forty-seven".