1981182641 has 4 divisors (see below), whose sum is σ = 1987512612. Its totient is φ = 1974852672.

The previous prime is 1981182629. The next prime is 1981182659. The reversal of 1981182641 is 1462811891.

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

It can be written as a sum of positive squares in 2 ways, for example, as 114597025 + 1866585616 = 10705^2 + 43204^2 .

It is a cyclic number.

It is not a de Polignac number, because 1981182641 - 2¹⁰ = 1981181617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981182661) 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, 3164516 + ... + 3165141.

It is an arithmetic number, because the mean of its divisors is an integer number (496878153).

Almost surely, 2^1981182641 is an apocalyptic number.

It is an amenable number.

1981182641 is a deficient number, since it is larger than the sum of its proper divisors (6329971).

1981182641 is an equidigital number, since it uses as much as digits as its factorization.

1981182641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6329970.

The product of its digits is 27648, while the sum is 41.

The square root of 1981182641 is about 44510.4778788096. The cubic root of 1981182641 is about 1255.9571944467.

The spelling of 1981182641 in words is "one billion, nine hundred eighty-one million, one hundred eighty-two thousand, six hundred forty-one".