21870193 has 2 divisors, whose sum is σ = 21870194. Its totient is φ = 21870192.

The previous prime is 21870169. The next prime is 21870209. The reversal of 21870193 is 39107812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17572864 + 4297329 = 4192^2 + 2073^2 .

It is a cyclic number.

It is not a de Polignac number, because 21870193 - 2⁵ = 21870161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21870103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10935096 + 10935097.

It is an arithmetic number, because the mean of its divisors is an integer number (10935097).

Almost surely, 2^21870193 is an apocalyptic number.

It is an amenable number.

21870193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21870193 is an equidigital number, since it uses as much as digits as its factorization.

21870193 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21870193 is about 4676.5578153167. The cubic root of 21870193 is about 279.6517481615.

The spelling of 21870193 in words is "twenty-one million, eight hundred seventy thousand, one hundred ninety-three".