21276649 has 2 divisors, whose sum is σ = 21276650. Its totient is φ = 21276648.

The previous prime is 21276643. The next prime is 21276667. The reversal of 21276649 is 94667212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17640000 + 3636649 = 4200^2 + 1907^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21276649 is a prime.

It is not a weakly prime, because it can be changed into another prime (21276643) 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, 10638324 + 10638325.

It is an arithmetic number, because the mean of its divisors is an integer number (10638325).

Almost surely, 2^21276649 is an apocalyptic number.

It is an amenable number.

21276649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21276649 is an equidigital number, since it uses as much as digits as its factorization.

21276649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 37.

The square root of 21276649 is about 4612.6618128798. The cubic root of 21276649 is about 277.0986498452.

The spelling of 21276649 in words is "twenty-one million, two hundred seventy-six thousand, six hundred forty-nine".