21680093 has 2 divisors, whose sum is σ = 21680094. Its totient is φ = 21680092.

The previous prime is 21680077. The next prime is 21680101. The reversal of 21680093 is 39008612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11580409 + 10099684 = 3403^2 + 3178^2 .

It is a cyclic number.

It is not a de Polignac number, because 21680093 - 2⁴ = 21680077 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21680003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10840046 + 10840047.

It is an arithmetic number, because the mean of its divisors is an integer number (10840047).

Almost surely, 2^21680093 is an apocalyptic number.

It is an amenable number.

21680093 is a deficient number, since it is larger than the sum of its proper divisors (1).

21680093 is an equidigital number, since it uses as much as digits as its factorization.

21680093 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 21680093 is about 4656.1886774485. The cubic root of 21680093 is about 278.8391265202.

The spelling of 21680093 in words is "twenty-one million, six hundred eighty thousand, ninety-three".