2164001581 has 4 divisors (see below), whose sum is σ = 2473144672. Its totient is φ = 1854858492.

The previous prime is 2164001579. The next prime is 2164001597. The reversal of 2164001581 is 1851004612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2164001581 - 2¹ = 2164001579 is a prime.

It is a super-2 number, since 2×2164001581² = 9365805685140999122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2164007581) 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, 154571535 + ... + 154571548.

It is an arithmetic number, because the mean of its divisors is an integer number (618286168).

Almost surely, 2^2164001581 is an apocalyptic number.

It is an amenable number.

2164001581 is a deficient number, since it is larger than the sum of its proper divisors (309143091).

2164001581 is an equidigital number, since it uses as much as digits as its factorization.

2164001581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309143090.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 2164001581 is about 46518.8303915737. The cubic root of 2164001581 is about 1293.4585757410.

The spelling of 2164001581 in words is "two billion, one hundred sixty-four million, one thousand, five hundred eighty-one".