21551113 has 2 divisors, whose sum is σ = 21551114. Its totient is φ = 21551112.

The previous prime is 21551071. The next prime is 21551119. The reversal of 21551113 is 31115512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20142144 + 1408969 = 4488^2 + 1187^2 .

It is a cyclic number.

It is not a de Polignac number, because 21551113 - 2⁹ = 21550601 is a prime.

It is equal to p_1362601 and since 21551113 and 1362601 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21551119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10775556 + 10775557.

It is an arithmetic number, because the mean of its divisors is an integer number (10775557).

Almost surely, 2^21551113 is an apocalyptic number.

It is an amenable number.

21551113 is a deficient number, since it is larger than the sum of its proper divisors (1).

21551113 is an equidigital number, since it uses as much as digits as its factorization.

21551113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 150, while the sum is 19.

The square root of 21551113 is about 4642.3176323901. The cubic root of 21551113 is about 278.2850663511.

Adding to 21551113 its reverse (31115512), we get a palindrome (52666625).

The spelling of 21551113 in words is "twenty-one million, five hundred fifty-one thousand, one hundred thirteen".