21394949 has 2 divisors, whose sum is σ = 21394950. Its totient is φ = 21394948.

The previous prime is 21394943. The next prime is 21395021. The reversal of 21394949 is 94949312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19272100 + 2122849 = 4390^2 + 1457^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21394949 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21394943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10697474 + 10697475.

It is an arithmetic number, because the mean of its divisors is an integer number (10697475).

Almost surely, 2^21394949 is an apocalyptic number.

It is an amenable number.

21394949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21394949 is an equidigital number, since it uses as much as digits as its factorization.

21394949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 41.

The square root of 21394949 is about 4625.4674358382. The cubic root of 21394949 is about 277.6112650698.

The spelling of 21394949 in words is "twenty-one million, three hundred ninety-four thousand, nine hundred forty-nine".