1621285109 has 4 divisors (see below), whose sum is σ = 1621586604. Its totient is φ = 1620983616.

The previous prime is 1621285091. The next prime is 1621285117. The reversal of 1621285109 is 9015821261.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1619821009 + 1464100 = 40247^2 + 1210^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621285109 - 2¹⁶ = 1621219573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621285139) 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, 142532 + ... + 153485.

It is an arithmetic number, because the mean of its divisors is an integer number (405396651).

Almost surely, 2^1621285109 is an apocalyptic number.

It is an amenable number.

1621285109 is a deficient number, since it is larger than the sum of its proper divisors (301495).

1621285109 is an equidigital number, since it uses as much as digits as its factorization.

1621285109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301494.

The product of its (nonzero) digits is 8640, while the sum is 35.

The square root of 1621285109 is about 40265.1848251067. The cubic root of 1621285109 is about 1174.7707677760.

The spelling of 1621285109 in words is "one billion, six hundred twenty-one million, two hundred eighty-five thousand, one hundred nine".