1611621681 has 16 divisors (see below), whose sum is σ = 2197219584. Its totient is φ = 1050274944.

The previous prime is 1611621679. The next prime is 1611621689. The reversal of 1611621681 is 1861261161.

It is not a de Polignac number, because 1611621681 - 2¹ = 1611621679 is a prime.

It is a super-2 number, since 2×1611621681² = 5194648885338531522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1611621689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 117141 + ... + 130173.

It is an arithmetic number, because the mean of its divisors is an integer number (137326224).

Almost surely, 2^1611621681 is an apocalyptic number.

It is an amenable number.

1611621681 is a deficient number, since it is larger than the sum of its proper divisors (585597903).

1611621681 is a wasteful number, since it uses less digits than its factorization.

1611621681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13960.

The product of its digits is 3456, while the sum is 33.

The square root of 1611621681 is about 40145.0081703815. The cubic root of 1611621681 is about 1172.4320998803.

The spelling of 1611621681 in words is "one billion, six hundred eleven million, six hundred twenty-one thousand, six hundred eighty-one".