21820273 has 2 divisors, whose sum is σ = 21820274. Its totient is φ = 21820272.

The previous prime is 21820243. The next prime is 21820283. The reversal of 21820273 is 37202812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12475024 + 9345249 = 3532^2 + 3057^2 .

It is a cyclic number.

It is not a de Polignac number, because 21820273 - 2¹³ = 21812081 is a prime.

It is a super-2 number, since 2×21820273² = 952248627589058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21820213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10910136 + 10910137.

It is an arithmetic number, because the mean of its divisors is an integer number (10910137).

Almost surely, 2^21820273 is an apocalyptic number.

It is an amenable number.

21820273 is a deficient number, since it is larger than the sum of its proper divisors (1).

21820273 is an equidigital number, since it uses as much as digits as its factorization.

21820273 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21820273 is about 4671.2175072458. The cubic root of 21820273 is about 279.4388122198.

The spelling of 21820273 in words is "twenty-one million, eight hundred twenty thousand, two hundred seventy-three".