10181581821 has 20 divisors (see below), whose sum is σ = 15270149664. Its totient is φ = 6760665000.

The previous prime is 10181581811. The next prime is 10181581859. The reversal of 10181581821 is 12818518101.

It is a happy number.

It is not a de Polignac number, because 10181581821 - 2⁵ = 10181581789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10181581811) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 230065 + ... + 270726.

Almost surely, 2^10181581821 is an apocalyptic number.

It is an amenable number.

10181581821 is a deficient number, since it is larger than the sum of its proper divisors (5088567843).

10181581821 is an equidigital number, since it uses as much as digits as its factorization.

10181581821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501054 (or 501045 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 36.

The spelling of 10181581821 in words is "ten billion, one hundred eighty-one million, five hundred eighty-one thousand, eight hundred twenty-one".