21401255 has 8 divisors (see below), whose sum is σ = 25790400. Its totient is φ = 17048416.

The previous prime is 21401251. The next prime is 21401257. The reversal of 21401255 is 55210412.

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 21401255 - 2² = 21401251 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21401251) 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 7 ways as a sum of consecutive naturals, for example, 7760 + ... + 10149.

It is an arithmetic number, because the mean of its divisors is an integer number (3223800).

Almost surely, 2^21401255 is an apocalyptic number.

21401255 is a deficient number, since it is larger than the sum of its proper divisors (4389145).

21401255 is a wasteful number, since it uses less digits than its factorization.

21401255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18153.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21401255 is about 4626.1490464532. The cubic root of 21401255 is about 277.6385370001.

Adding to 21401255 its reverse (55210412), we get a palindrome (76611667).

The spelling of 21401255 in words is "twenty-one million, four hundred one thousand, two hundred fifty-five".