21360253 has 2 divisors, whose sum is σ = 21360254. Its totient is φ = 21360252.

The previous prime is 21360247. The next prime is 21360259. The reversal of 21360253 is 35206312.

It is a balanced prime because it is at equal distance from previous prime (21360247) and next prime (21360259).

It can be written as a sum of positive squares in only one way, i.e., 15705369 + 5654884 = 3963^2 + 2378^2 .

It is a cyclic number.

It is not a de Polignac number, because 21360253 - 2¹³ = 21352061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21360259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10680126 + 10680127.

It is an arithmetic number, because the mean of its divisors is an integer number (10680127).

Almost surely, 2^21360253 is an apocalyptic number.

It is an amenable number.

21360253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21360253 is an equidigital number, since it uses as much as digits as its factorization.

21360253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 21360253 is about 4621.7153741874. The cubic root of 21360253 is about 277.4611172965.

Adding to 21360253 its reverse (35206312), we get a palindrome (56566565).

The spelling of 21360253 in words is "twenty-one million, three hundred sixty thousand, two hundred fifty-three".