21370055 has 16 divisors (see below), whose sum is σ = 29501760. Its totient is φ = 14556672.

The previous prime is 21370049. The next prime is 21370087. The reversal of 21370055 is 55007312.

It is a cyclic number.

It is not a de Polignac number, because 21370055 - 2⁴ = 21370039 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21370055.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3551 + ... + 7439.

It is an arithmetic number, because the mean of its divisors is an integer number (1843860).

Almost surely, 2^21370055 is an apocalyptic number.

21370055 is a deficient number, since it is larger than the sum of its proper divisors (8131705).

21370055 is a wasteful number, since it uses less digits than its factorization.

21370055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4058.

The product of its (nonzero) digits is 1050, while the sum is 23.

The square root of 21370055 is about 4622.7756813412. The cubic root of 21370055 is about 277.5035521554.

Adding to 21370055 its reverse (55007312), we get a palindrome (76377367).

The spelling of 21370055 in words is "twenty-one million, three hundred seventy thousand, fifty-five".