2006861821 has 2 divisors, whose sum is σ = 2006861822. Its totient is φ = 2006861820.

The previous prime is 2006861777. The next prime is 2006861839. The reversal of 2006861821 is 1281686002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1876102596 + 130759225 = 43314^2 + 11435^2 .

It is a cyclic number.

It is not a de Polignac number, because 2006861821 - 2⁷ = 2006861693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2006861851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1003430910 + 1003430911.

It is an arithmetic number, because the mean of its divisors is an integer number (1003430911).

Almost surely, 2^2006861821 is an apocalyptic number.

It is an amenable number.

2006861821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2006861821 is an equidigital number, since it uses as much as digits as its factorization.

2006861821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 2006861821 is about 44798.0113509517. The cubic root of 2006861821 is about 1261.3602972911.

The spelling of 2006861821 in words is "two billion, six million, eight hundred sixty-one thousand, eight hundred twenty-one".