21385955 has 8 divisors (see below), whose sum is σ = 25734192. Its totient is φ = 17061408.

The previous prime is 21385951. The next prime is 21385961. The reversal of 21385955 is 55958312.

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 21385955 - 2² = 21385951 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21385951) 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, 3869 + ... + 7598.

It is an arithmetic number, because the mean of its divisors is an integer number (3216774).

Almost surely, 2^21385955 is an apocalyptic number.

21385955 is a deficient number, since it is larger than the sum of its proper divisors (4348237).

21385955 is a wasteful number, since it uses less digits than its factorization.

21385955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11845.

The product of its digits is 54000, while the sum is 38.

The square root of 21385955 is about 4624.4951075766. The cubic root of 21385955 is about 277.5723589138.

It can be divided in two parts, 213 and 85955, that added together give a palindrome (86168).

The spelling of 21385955 in words is "twenty-one million, three hundred eighty-five thousand, nine hundred fifty-five".