21260749 has 2 divisors, whose sum is σ = 21260750. Its totient is φ = 21260748.

The previous prime is 21260711. The next prime is 21260797. The reversal of 21260749 is 94706212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21252100 + 8649 = 4610^2 + 93^2 .

It is a cyclic number.

It is not a de Polignac number, because 21260749 - 2⁷ = 21260621 is a prime.

It is a plaindrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 21260749.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21260549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630374 + 10630375.

It is an arithmetic number, because the mean of its divisors is an integer number (10630375).

Almost surely, 2^21260749 is an apocalyptic number.

It is an amenable number.

21260749 is a deficient number, since it is larger than the sum of its proper divisors (1).

21260749 is an equidigital number, since it uses as much as digits as its factorization.

21260749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 21260749 is about 4610.9379739918. The cubic root of 21260749 is about 277.0296075431.

The spelling of 21260749 in words is "twenty-one million, two hundred sixty thousand, seven hundred forty-nine".