1601621111 has 4 divisors (see below), whose sum is σ = 1607531424. Its totient is φ = 1595710800.

The previous prime is 1601621081. The next prime is 1601621113. The reversal of 1601621111 is 1111261061.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1601621111 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 (1601621113) 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, 2954750 + ... + 2955291.

It is an arithmetic number, because the mean of its divisors is an integer number (401882856).

Almost surely, 2^1601621111 is an apocalyptic number.

1601621111 is a deficient number, since it is larger than the sum of its proper divisors (5910313).

1601621111 is an equidigital number, since it uses as much as digits as its factorization.

1601621111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5910312.

The product of its (nonzero) digits is 72, while the sum is 20.

The square root of 1601621111 is about 40020.2587572844. The cubic root of 1601621111 is about 1170.0019750618.

Adding to 1601621111 its reverse (1111261061), we get a palindrome (2712882172).

The spelling of 1601621111 in words is "one billion, six hundred one million, six hundred twenty-one thousand, one hundred eleven".