1621604161 has 8 divisors (see below), whose sum is σ = 1663981704. Its totient is φ = 1579361280.

The previous prime is 1621604137. The next prime is 1621604183. The reversal of 1621604161 is 1614061261.

It can be written as a sum of positive squares in 4 ways, for example, as 56927025 + 1564677136 = 7545^2 + 39556^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1621604161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1621604561) 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, 9036 + ... + 57661.

It is an arithmetic number, because the mean of its divisors is an integer number (207997713).

Almost surely, 2^1621604161 is an apocalyptic number.

It is an amenable number.

1621604161 is a deficient number, since it is larger than the sum of its proper divisors (42377543).

1621604161 is an equidigital number, since it uses as much as digits as its factorization.

1621604161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67331.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 1621604161 is about 40269.1465144222. The cubic root of 1621604161 is about 1174.8478235999.

The spelling of 1621604161 in words is "one billion, six hundred twenty-one million, six hundred four thousand, one hundred sixty-one".