21352687 has 2 divisors, whose sum is σ = 21352688. Its totient is φ = 21352686.

The previous prime is 21352651. The next prime is 21352691. The reversal of 21352687 is 78625312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21352687 - 2⁷ = 21352559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21352627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10676343 + 10676344.

It is an arithmetic number, because the mean of its divisors is an integer number (10676344).

Almost surely, 2^21352687 is an apocalyptic number.

21352687 is a deficient number, since it is larger than the sum of its proper divisors (1).

21352687 is an equidigital number, since it uses as much as digits as its factorization.

21352687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 34.

The square root of 21352687 is about 4620.8967744368. The cubic root of 21352687 is about 277.4283536595.

Adding to 21352687 its reverse (78625312), we get a palindrome (99977999).

It can be divided in two parts, 213 and 52687, that added together give a square (52900 = 230²).

The spelling of 21352687 in words is "twenty-one million, three hundred fifty-two thousand, six hundred eighty-seven".