21275983 has 2 divisors, whose sum is σ = 21275984. Its totient is φ = 21275982.

The previous prime is 21275981. The next prime is 21276023. The reversal of 21275983 is 38957212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21275983 - 2¹ = 21275981 is a prime.

Together with 21275981, 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 (21275981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10637991 + 10637992.

It is an arithmetic number, because the mean of its divisors is an integer number (10637992).

Almost surely, 2^21275983 is an apocalyptic number.

21275983 is a deficient number, since it is larger than the sum of its proper divisors (1).

21275983 is an equidigital number, since it uses as much as digits as its factorization.

21275983 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 37.

The square root of 21275983 is about 4612.5896197256. The cubic root of 21275983 is about 277.0957585750.

The spelling of 21275983 in words is "twenty-one million, two hundred seventy-five thousand, nine hundred eighty-three".