21283751 has 2 divisors, whose sum is σ = 21283752. Its totient is φ = 21283750.

The previous prime is 21283739. The next prime is 21283771. The reversal of 21283751 is 15738212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21283751 - 2¹⁰ = 21282727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21283721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10641875 + 10641876.

It is an arithmetic number, because the mean of its divisors is an integer number (10641876).

Almost surely, 2^21283751 is an apocalyptic number.

21283751 is a deficient number, since it is larger than the sum of its proper divisors (1).

21283751 is an equidigital number, since it uses as much as digits as its factorization.

21283751 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3360, while the sum is 29.

The square root of 21283751 is about 4613.4315861406. The cubic root of 21283751 is about 277.1294776272.

The spelling of 21283751 in words is "twenty-one million, two hundred eighty-three thousand, seven hundred fifty-one".