21070549 has 2 divisors, whose sum is σ = 21070550. Its totient is φ = 21070548.

The previous prime is 21070541. The next prime is 21070579. The reversal of 21070549 is 94507012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13089924 + 7980625 = 3618^2 + 2825^2 .

It is a cyclic number.

It is not a de Polignac number, because 21070549 - 2³ = 21070541 is a prime.

It is a super-2 number, since 2×21070549² = 887936070322802, which contains 22 as substring.

It is a Chen 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 (21070541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10535274 + 10535275.

It is an arithmetic number, because the mean of its divisors is an integer number (10535275).

Almost surely, 2^21070549 is an apocalyptic number.

It is an amenable number.

21070549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21070549 is an equidigital number, since it uses as much as digits as its factorization.

21070549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21070549 is about 4590.2667678469. The cubic root of 21070549 is about 276.2010236469.

The spelling of 21070549 in words is "twenty-one million, seventy thousand, five hundred forty-nine".