21036493 has 2 divisors, whose sum is σ = 21036494. Its totient is φ = 21036492.

The previous prime is 21036481. The next prime is 21036511. The reversal of 21036493 is 39463012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17280649 + 3755844 = 4157^2 + 1938^2 .

It is a cyclic number.

It is not a de Polignac number, because 21036493 - 2⁹ = 21035981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21036413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10518246 + 10518247.

It is an arithmetic number, because the mean of its divisors is an integer number (10518247).

Almost surely, 2^21036493 is an apocalyptic number.

It is an amenable number.

21036493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21036493 is an equidigital number, since it uses as much as digits as its factorization.

21036493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 21036493 is about 4586.5556793742. Note that the first 3 decimals coincide. The cubic root of 21036493 is about 276.0521369335.

The spelling of 21036493 in words is "twenty-one million, thirty-six thousand, four hundred ninety-three".