21300649 has 2 divisors, whose sum is σ = 21300650. Its totient is φ = 21300648.

The previous prime is 21300619. The next prime is 21300659. The reversal of 21300649 is 94600312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21114025 + 186624 = 4595^2 + 432^2 .

It is a cyclic number.

It is not a de Polignac number, because 21300649 - 2⁹ = 21300137 is a prime.

It is not a weakly prime, because it can be changed into another prime (21300619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650324 + 10650325.

It is an arithmetic number, because the mean of its divisors is an integer number (10650325).

Almost surely, 2^21300649 is an apocalyptic number.

It is an amenable number.

21300649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21300649 is an equidigital number, since it uses as much as digits as its factorization.

21300649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 21300649 is about 4615.2626144132. The cubic root of 21300649 is about 277.2027995264.

The spelling of 21300649 in words is "twenty-one million, three hundred thousand, six hundred forty-nine".