21014551 has 4 divisors (see below), whose sum is σ = 22120600. Its totient is φ = 19908504.

The previous prime is 21014527. The next prime is 21014579. The reversal of 21014551 is 15541012.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21014551 - 2¹¹ = 21012503 is a prime.

It is a super-2 number, since 2×21014551² = 883222707463202, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 1106029 = 21014551 / (2 + 1 + 0 + 1 + 4 + 5 + 5 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21014501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 552996 + ... + 553033.

It is an arithmetic number, because the mean of its divisors is an integer number (5530150).

Almost surely, 2^21014551 is an apocalyptic number.

21014551 is a deficient number, since it is larger than the sum of its proper divisors (1106049).

21014551 is a wasteful number, since it uses less digits than its factorization.

21014551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1106048.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 21014551 is about 4584.1630642899. The cubic root of 21014551 is about 275.9561253159.

Adding to 21014551 its reverse (15541012), we get a palindrome (36555563).

The spelling of 21014551 in words is "twenty-one million, fourteen thousand, five hundred fifty-one".