1620698909 has 2 divisors, whose sum is σ = 1620698910. Its totient is φ = 1620698908.

The previous prime is 1620698897. The next prime is 1620698953. The reversal of 1620698909 is 9098960261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 815388025 + 805310884 = 28555^2 + 28378^2 .

It is a cyclic number.

It is not a de Polignac number, because 1620698909 - 2¹⁶ = 1620633373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1620668909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810349454 + 810349455.

It is an arithmetic number, because the mean of its divisors is an integer number (810349455).

Almost surely, 2^1620698909 is an apocalyptic number.

It is an amenable number.

1620698909 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620698909 is an equidigital number, since it uses as much as digits as its factorization.

1620698909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 1620698909 is about 40257.9049256168. The cubic root of 1620698909 is about 1174.6291653657.

The spelling of 1620698909 in words is "one billion, six hundred twenty million, six hundred ninety-eight thousand, nine hundred nine".