21070949 has 2 divisors, whose sum is σ = 21070950. Its totient is φ = 21070948.

The previous prime is 21070937. The next prime is 21070969. The reversal of 21070949 is 94907012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20702500 + 368449 = 4550^2 + 607^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21070949 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21070909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10535474 + 10535475.

It is an arithmetic number, because the mean of its divisors is an integer number (10535475).

Almost surely, 2^21070949 is an apocalyptic number.

It is an amenable number.

21070949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21070949 is an equidigital number, since it uses as much as digits as its factorization.

21070949 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 21070949 is about 4590.3103380926. The cubic root of 21070949 is about 276.2027714215.

The spelling of 21070949 in words is "twenty-one million, seventy thousand, nine hundred forty-nine".