1981800827 has 4 divisors (see below), whose sum is σ = 1992872520. Its totient is φ = 1970729136.

The previous prime is 1981800817. The next prime is 1981800851. The reversal of 1981800827 is 7280081891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7280081891 = 9091 ⋅800801.

It is a cyclic number.

It is not a de Polignac number, because 1981800827 - 2¹⁶ = 1981735291 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981800817) 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, 5535578 + ... + 5535935.

It is an arithmetic number, because the mean of its divisors is an integer number (498218130).

Almost surely, 2^1981800827 is an apocalyptic number.

1981800827 is a deficient number, since it is larger than the sum of its proper divisors (11071693).

1981800827 is a wasteful number, since it uses less digits than its factorization.

1981800827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11071692.

The product of its (nonzero) digits is 64512, while the sum is 44.

The square root of 1981800827 is about 44517.4216122183. The cubic root of 1981800827 is about 1256.0878124586.

The spelling of 1981800827 in words is "one billion, nine hundred eighty-one million, eight hundred thousand, eight hundred twenty-seven".