21116351 has 2 divisors, whose sum is σ = 21116352. Its totient is φ = 21116350.

The previous prime is 21116317. The next prime is 21116357. The reversal of 21116351 is 15361112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21116351 - 2⁶ = 21116287 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21116357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10558175 + 10558176.

It is an arithmetic number, because the mean of its divisors is an integer number (10558176).

Almost surely, 2^21116351 is an apocalyptic number.

21116351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21116351 is an equidigital number, since it uses as much as digits as its factorization.

21116351 is an evil number, because the sum of its binary digits is even.

The product of its digits is 180, while the sum is 20.

The square root of 21116351 is about 4595.2530942267. The cubic root of 21116351 is about 276.4010090068.

Adding to 21116351 its reverse (15361112), we get a palindrome (36477463).

The spelling of 21116351 in words is "twenty-one million, one hundred sixteen thousand, three hundred fifty-one".