21700949 has 2 divisors, whose sum is σ = 21700950. Its totient is φ = 21700948.

The previous prime is 21700901. The next prime is 21700957. The reversal of 21700949 is 94900712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19298449 + 2402500 = 4393^2 + 1550^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21700949 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 (21700969) 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, 10850474 + 10850475.

It is an arithmetic number, because the mean of its divisors is an integer number (10850475).

Almost surely, 2^21700949 is an apocalyptic number.

It is an amenable number.

21700949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21700949 is an equidigital number, since it uses as much as digits as its factorization.

21700949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 21700949 is about 4658.4277390553. The cubic root of 21700949 is about 278.9285112077.

The spelling of 21700949 in words is "twenty-one million, seven hundred thousand, nine hundred forty-nine".