1620913609 has 4 divisors (see below), whose sum is σ = 1852472704. Its totient is φ = 1389354516.

The previous prime is 1620913607. The next prime is 1620913621. The reversal of 1620913609 is 9063190261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9063190261 = 41 ⋅221053421.

It is a cyclic number.

It is not a de Polignac number, because 1620913609 - 2¹ = 1620913607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1620913607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 115779537 + ... + 115779550.

It is an arithmetic number, because the mean of its divisors is an integer number (463118176).

Almost surely, 2^1620913609 is an apocalyptic number.

It is an amenable number.

1620913609 is a deficient number, since it is larger than the sum of its proper divisors (231559095).

1620913609 is an equidigital number, since it uses as much as digits as its factorization.

1620913609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231559094.

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 1620913609 is about 40260.5713943555. The cubic root of 1620913609 is about 1174.6810322372.

The spelling of 1620913609 in words is "one billion, six hundred twenty million, nine hundred thirteen thousand, six hundred nine".