21554135 has 4 divisors (see below), whose sum is σ = 25864968. Its totient is φ = 17243304.

The previous prime is 21554111. The next prime is 21554149. The reversal of 21554135 is 53145512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21554135 - 2¹⁰ = 21553111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2155409 + ... + 2155418.

It is an arithmetic number, because the mean of its divisors is an integer number (6466242).

Almost surely, 2^21554135 is an apocalyptic number.

21554135 is a deficient number, since it is larger than the sum of its proper divisors (4310833).

21554135 is an equidigital number, since it uses as much as digits as its factorization.

21554135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4310832.

The product of its digits is 3000, while the sum is 26.

The square root of 21554135 is about 4642.6431049565. The cubic root of 21554135 is about 278.2980732302.

Adding to 21554135 its reverse (53145512), we get a palindrome (74699647).

The spelling of 21554135 in words is "twenty-one million, five hundred fifty-four thousand, one hundred thirty-five".