1021868181 has 12 divisors (see below), whose sum is σ = 1562857452. Its totient is φ = 641172096.

The previous prime is 1021868179. The next prime is 1021868191. The reversal of 1021868181 is 1818681201.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 859076100 + 162792081 = 29310^2 + 12759^2 .

It is not a de Polignac number, because 1021868181 - 2¹ = 1021868179 is a prime.

It is a super-2 number, since 2×1021868181² = 2088429158680497522, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021868191) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3339286 + ... + 3339591.

It is an arithmetic number, because the mean of its divisors is an integer number (130238121).

Almost surely, 2^1021868181 is an apocalyptic number.

It is an amenable number.

1021868181 is a deficient number, since it is larger than the sum of its proper divisors (540989271).

1021868181 is a wasteful number, since it uses less digits than its factorization.

1021868181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6678900 (or 6678897 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 36.

The square root of 1021868181 is about 31966.6729735830. The cubic root of 1021868181 is about 1007.2368946836.

The spelling of 1021868181 in words is "one billion, twenty-one million, eight hundred sixty-eight thousand, one hundred eighty-one".