21060551 has 2 divisors, whose sum is σ = 21060552. Its totient is φ = 21060550.

The previous prime is 21060541. The next prime is 21060553. The reversal of 21060551 is 15506012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21060551 is a prime.

Together with 21060553, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21060553) 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 as a sum of consecutive naturals, namely, 10530275 + 10530276.

It is an arithmetic number, because the mean of its divisors is an integer number (10530276).

Almost surely, 2^21060551 is an apocalyptic number.

21060551 is a deficient number, since it is larger than the sum of its proper divisors (1).

21060551 is an equidigital number, since it uses as much as digits as its factorization.

21060551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 21060551 is about 4589.1775951689. The cubic root of 21060551 is about 276.1573308331.

Adding to 21060551 its reverse (15506012), we get a palindrome (36566563).

The spelling of 21060551 in words is "twenty-one million, sixty thousand, five hundred fifty-one".