21135455 has 16 divisors (see below), whose sum is σ = 27796608. Its totient is φ = 15300000.

The previous prime is 21135451. The next prime is 21135479. The reversal of 21135455 is 55453112.

It is not a de Polignac number, because 21135455 - 2² = 21135451 is a prime.

It is a Duffinian number.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21135451) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13040 + ... + 14570.

It is an arithmetic number, because the mean of its divisors is an integer number (1737288).

Almost surely, 2^21135455 is an apocalyptic number.

21135455 is a deficient number, since it is larger than the sum of its proper divisors (6661153).

21135455 is a wasteful number, since it uses less digits than its factorization.

21135455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1798.

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

The square root of 21135455 is about 4597.3312910862. The cubic root of 21135455 is about 276.4843373762.

Adding to 21135455 its reverse (55453112), we get a palindrome (76588567).

The spelling of 21135455 in words is "twenty-one million, one hundred thirty-five thousand, four hundred fifty-five".