21150055 has 8 divisors (see below), whose sum is σ = 25999344. Its totient is φ = 16507200.

The previous prime is 21150043. The next prime is 21150061. The reversal of 21150055 is 55005112.

21150055 = 1875² + 1876² + ... + 1880².

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21150055 - 2⁷ = 21149927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 51381 + ... + 51790.

It is an arithmetic number, because the mean of its divisors is an integer number (3249918).

Almost surely, 2^21150055 is an apocalyptic number.

21150055 is a deficient number, since it is larger than the sum of its proper divisors (4849289).

21150055 is a wasteful number, since it uses less digits than its factorization.

21150055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103217.

The product of its (nonzero) digits is 250, while the sum is 19.

The square root of 21150055 is about 4598.9188946969. The cubic root of 21150055 is about 276.5479862259.

Adding to 21150055 its reverse (55005112), we get a palindrome (76155167).

The spelling of 21150055 in words is "twenty-one million, one hundred fifty thousand, fifty-five".