21013061 has 2 divisors, whose sum is σ = 21013062. Its totient is φ = 21013060.

The previous prime is 21013049. The next prime is 21013063. The reversal of 21013061 is 16031012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19412836 + 1600225 = 4406^2 + 1265^2 .

It is a cyclic number.

It is not a de Polignac number, because 21013061 - 2⁶ = 21012997 is a prime.

Together with 21013063, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21013063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506530 + 10506531.

It is an arithmetic number, because the mean of its divisors is an integer number (10506531).

Almost surely, 2^21013061 is an apocalyptic number.

It is an amenable number.

21013061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21013061 is an equidigital number, since it uses as much as digits as its factorization.

21013061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 21013061 is about 4584.0005453752. Note that the first 3 decimals coincide. The cubic root of 21013061 is about 275.9496030996.

Adding to 21013061 its reverse (16031012), we get a palindrome (37044073).

The spelling of 21013061 in words is "twenty-one million, thirteen thousand, sixty-one".