21532087 has 2 divisors, whose sum is σ = 21532088. Its totient is φ = 21532086.

The previous prime is 21532067. The next prime is 21532097. The reversal of 21532087 is 78023512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21532087 - 2¹⁹ = 21007799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21532067) 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, 10766043 + 10766044.

It is an arithmetic number, because the mean of its divisors is an integer number (10766044).

Almost surely, 2^21532087 is an apocalyptic number.

21532087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21532087 is an equidigital number, since it uses as much as digits as its factorization.

21532087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 21532087 is about 4640.2679879507. The cubic root of 21532087 is about 278.2031493053.

Adding to 21532087 its reverse (78023512), we get a palindrome (99555599).

The spelling of 21532087 in words is "twenty-one million, five hundred thirty-two thousand, eighty-seven".