21567151 has 2 divisors, whose sum is σ = 21567152. Its totient is φ = 21567150.

The previous prime is 21567137. The next prime is 21567157. The reversal of 21567151 is 15176512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21567151 - 2¹⁹ = 21042863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21567157) 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, 10783575 + 10783576.

It is an arithmetic number, because the mean of its divisors is an integer number (10783576).

Almost surely, 2^21567151 is an apocalyptic number.

21567151 is a deficient number, since it is larger than the sum of its proper divisors (1).

21567151 is an equidigital number, since it uses as much as digits as its factorization.

21567151 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2100, while the sum is 28.

The square root of 21567151 is about 4644.0446810943. The cubic root of 21567151 is about 278.3540810268.

The spelling of 21567151 in words is "twenty-one million, five hundred sixty-seven thousand, one hundred fifty-one".