20270821 has 2 divisors, whose sum is σ = 20270822. Its totient is φ = 20270820.

The previous prime is 20270791. The next prime is 20270827. The reversal of 20270821 is 12807202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13793796 + 6477025 = 3714^2 + 2545^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20270821 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20270792 and 20270801.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20270827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10135410 + 10135411.

It is an arithmetic number, because the mean of its divisors is an integer number (10135411).

Almost surely, 2^20270821 is an apocalyptic number.

It is an amenable number.

20270821 is a deficient number, since it is larger than the sum of its proper divisors (1).

20270821 is an equidigital number, since it uses as much as digits as its factorization.

20270821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 20270821 is about 4502.3128500805. The cubic root of 20270821 is about 272.6614748711.

The spelling of 20270821 in words is "twenty million, two hundred seventy thousand, eight hundred twenty-one".