1881642157 has 4 divisors (see below), whose sum is σ = 1882073340. Its totient is φ = 1881210976.

The previous prime is 1881642149. The next prime is 1881642251. The reversal of 1881642157 is 7512461881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7512461881 = 241 ⋅31172041.

It can be written as a sum of positive squares in 2 ways, for example, as 448338276 + 1433303881 = 21174^2 + 37859^2 .

It is a cyclic number.

It is not a de Polignac number, because 1881642157 - 2³ = 1881642149 is a prime.

It is a super-2 number, since 2×1881642157² = 7081154413999225298, 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 (1881642107) 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, 208978 + ... + 217795.

It is an arithmetic number, because the mean of its divisors is an integer number (470518335).

Almost surely, 2^1881642157 is an apocalyptic number.

It is an amenable number.

1881642157 is a deficient number, since it is larger than the sum of its proper divisors (431183).

1881642157 is an equidigital number, since it uses as much as digits as its factorization.

1881642157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431182.

The product of its digits is 107520, while the sum is 43.

The square root of 1881642157 is about 43377.8994074171. The cubic root of 1881642157 is about 1234.5604071801.

The spelling of 1881642157 in words is "one billion, eight hundred eighty-one million, six hundred forty-two thousand, one hundred fifty-seven".