21352109 has 2 divisors, whose sum is σ = 21352110. Its totient is φ = 21352108.

The previous prime is 21352099. The next prime is 21352127. The reversal of 21352109 is 90125312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16176484 + 5175625 = 4022^2 + 2275^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21352109 is a prime.

It is a Chen prime.

It is a plaindrome in base 13.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21352139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10676054 + 10676055.

It is an arithmetic number, because the mean of its divisors is an integer number (10676055).

Almost surely, 2^21352109 is an apocalyptic number.

It is an amenable number.

21352109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21352109 is an equidigital number, since it uses as much as digits as its factorization.

21352109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 21352109 is about 4620.8342320408. The cubic root of 21352109 is about 277.4258503831.

The spelling of 21352109 in words is "twenty-one million, three hundred fifty-two thousand, one hundred nine".