1020651209 has 2 divisors, whose sum is σ = 1020651210. Its totient is φ = 1020651208.

The previous prime is 1020651193. The next prime is 1020651221. The reversal of 1020651209 is 9021560201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 989291209 + 31360000 = 31453^2 + 5600^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020651209 - 2⁴ = 1020651193 is a prime.

It is not a weakly prime, because it can be changed into another prime (1020651239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510325604 + 510325605.

It is an arithmetic number, because the mean of its divisors is an integer number (510325605).

Almost surely, 2^1020651209 is an apocalyptic number.

It is an amenable number.

1020651209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020651209 is an equidigital number, since it uses as much as digits as its factorization.

1020651209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 1020651209 is about 31947.6322909852. The cubic root of 1020651209 is about 1006.8368867868.

The spelling of 1020651209 in words is "one billion, twenty million, six hundred fifty-one thousand, two hundred nine".