21963751 has 2 divisors, whose sum is σ = 21963752. Its totient is φ = 21963750.

The previous prime is 21963743. The next prime is 21963757. The reversal of 21963751 is 15736912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21963751 - 2³ = 21963743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21963757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10981875 + 10981876.

It is an arithmetic number, because the mean of its divisors is an integer number (10981876).

Almost surely, 2^21963751 is an apocalyptic number.

21963751 is a deficient number, since it is larger than the sum of its proper divisors (1).

21963751 is an equidigital number, since it uses as much as digits as its factorization.

21963751 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11340, while the sum is 34.

The square root of 21963751 is about 4686.5500104021. The cubic root of 21963751 is about 280.0499528224.

The spelling of 21963751 in words is "twenty-one million, nine hundred sixty-three thousand, seven hundred fifty-one".