21738751 has 2 divisors, whose sum is σ = 21738752. Its totient is φ = 21738750.

The previous prime is 21738737. The next prime is 21738763. The reversal of 21738751 is 15783712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21738751 - 2⁷ = 21738623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21738701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10869375 + 10869376.

It is an arithmetic number, because the mean of its divisors is an integer number (10869376).

Almost surely, 2^21738751 is an apocalyptic number.

21738751 is a deficient number, since it is larger than the sum of its proper divisors (1).

21738751 is an equidigital number, since it uses as much as digits as its factorization.

21738751 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11760, while the sum is 34.

The square root of 21738751 is about 4662.4833511767. The cubic root of 21738751 is about 279.0903772331.

The spelling of 21738751 in words is "twenty-one million, seven hundred thirty-eight thousand, seven hundred fifty-one".