21260501 has 2 divisors, whose sum is σ = 21260502. Its totient is φ = 21260500.

The previous prime is 21260483. The next prime is 21260521. The reversal of 21260501 is 10506212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20160100 + 1100401 = 4490^2 + 1049^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21260501 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21260501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21260521) 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, 10630250 + 10630251.

It is an arithmetic number, because the mean of its divisors is an integer number (10630251).

Almost surely, 2^21260501 is an apocalyptic number.

It is an amenable number.

21260501 is a deficient number, since it is larger than the sum of its proper divisors (1).

21260501 is an equidigital number, since it uses as much as digits as its factorization.

21260501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21260501 is about 4610.9110813374. The cubic root of 21260501 is about 277.0285303842.

Adding to 21260501 its reverse (10506212), we get a palindrome (31766713).

The spelling of 21260501 in words is "twenty-one million, two hundred sixty thousand, five hundred one".