21527851 has 2 divisors, whose sum is σ = 21527852. Its totient is φ = 21527850.

The previous prime is 21527813. The next prime is 21527867. The reversal of 21527851 is 15872512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21527851 - 2¹⁵ = 21495083 is a prime.

It is not a weakly prime, because it can be changed into another prime (21527881) 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, 10763925 + 10763926.

It is an arithmetic number, because the mean of its divisors is an integer number (10763926).

Almost surely, 2^21527851 is an apocalyptic number.

21527851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21527851 is an equidigital number, since it uses as much as digits as its factorization.

21527851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5600, while the sum is 31.

The square root of 21527851 is about 4639.8115263446. The cubic root of 21527851 is about 278.1849045058.

The spelling of 21527851 in words is "twenty-one million, five hundred twenty-seven thousand, eight hundred fifty-one".