21036751 has 2 divisors, whose sum is σ = 21036752. Its totient is φ = 21036750.

The previous prime is 21036749. The next prime is 21036767. The reversal of 21036751 is 15763012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21036751 - 2¹ = 21036749 is a prime.

Together with 21036749, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21036721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10518375 + 10518376.

It is an arithmetic number, because the mean of its divisors is an integer number (10518376).

Almost surely, 2^21036751 is an apocalyptic number.

21036751 is a deficient number, since it is larger than the sum of its proper divisors (1).

21036751 is an equidigital number, since it uses as much as digits as its factorization.

21036751 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 21036751 is about 4586.5838049686. The cubic root of 21036751 is about 276.0532654670.

Adding to 21036751 its reverse (15763012), we get a palindrome (36799763).

The spelling of 21036751 in words is "twenty-one million, thirty-six thousand, seven hundred fifty-one".