1881664541 has 4 divisors (see below), whose sum is σ = 1886030784. Its totient is φ = 1877298300.

The previous prime is 1881664483. The next prime is 1881664553. The reversal of 1881664541 is 1454661881.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1454661881 = 17609 ⋅82609.

It is a cyclic number.

It is not a de Polignac number, because 1881664541 - 2¹⁰ = 1881663517 is a prime.

It is a super-2 number, since 2×1881664541² = 7081322889713481362, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1881664492 and 1881664501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1881663541) 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, 2182475 + ... + 2183336.

It is an arithmetic number, because the mean of its divisors is an integer number (471507696).

Almost surely, 2^1881664541 is an apocalyptic number.

It is an amenable number.

1881664541 is a deficient number, since it is larger than the sum of its proper divisors (4366243).

1881664541 is an equidigital number, since it uses as much as digits as its factorization.

1881664541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4366242.

The product of its digits is 184320, while the sum is 44.

The square root of 1881664541 is about 43378.1574182214. The cubic root of 1881664541 is about 1234.5653026009.

The spelling of 1881664541 in words is "one billion, eight hundred eighty-one million, six hundred sixty-four thousand, five hundred forty-one".