2181975826 has 4 divisors (see below), whose sum is σ = 3272963742. Its totient is φ = 1090987912.

The previous prime is 2181975769. The next prime is 2181975833. The reversal of 2181975826 is 6285791812.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 1115626801 + 1066349025 = 33401^2 + 32655^2 .

It is a super-2 number, since 2×2181975826² = 9522037010496764552, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 2181975826.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545493955 + ... + 545493958.

Almost surely, 2^2181975826 is an apocalyptic number.

2181975826 is a deficient number, since it is larger than the sum of its proper divisors (1090987916).

2181975826 is a wasteful number, since it uses less digits than its factorization.

2181975826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1090987915.

The product of its digits is 483840, while the sum is 49.

The square root of 2181975826 is about 46711.6240993610. The cubic root of 2181975826 is about 1297.0298713434.

The spelling of 2181975826 in words is "two billion, one hundred eighty-one million, nine hundred seventy-five thousand, eight hundred twenty-six".