1621264165 has 8 divisors (see below), whose sum is σ = 1959718680. Its totient is φ = 1287543552.

The previous prime is 1621264163. The next prime is 1621264171. The reversal of 1621264165 is 5614621261.

It can be written as a sum of positive squares in 4 ways, for example, as 255296484 + 1365967681 = 15978^2 + 36959^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1621264165 - 2¹ = 1621264163 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1621264165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621264163) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1182720 + ... + 1184089.

It is an arithmetic number, because the mean of its divisors is an integer number (244964835).

Almost surely, 2^1621264165 is an apocalyptic number.

It is an amenable number.

1621264165 is a deficient number, since it is larger than the sum of its proper divisors (338454515).

1621264165 is a wasteful number, since it uses less digits than its factorization.

1621264165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2366951.

The product of its digits is 17280, while the sum is 34.

The square root of 1621264165 is about 40264.9247484706. The cubic root of 1621264165 is about 1174.7657091336.

The spelling of 1621264165 in words is "one billion, six hundred twenty-one million, two hundred sixty-four thousand, one hundred sixty-five".