81330021400 has 24 divisors (see below), whose sum is σ = 189092300220. Its totient is φ = 32532008480.

The previous prime is 81330021391. The next prime is 81330021433. The reversal of 81330021400 is 412003318.

It is a super-2 number, since 2×81330021400² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 203324854 + ... + 203325253.

Almost surely, 2^81330021400 is an apocalyptic number.

It is an amenable number.

81330021400 is an abundant number, since it is smaller than the sum of its proper divisors (107762278820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81330021400 is a wasteful number, since it uses less digits than its factorization.

81330021400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406650123 (or 406650114 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

Adding to 81330021400 its reverse (412003318), we get a palindrome (81742024718).

The spelling of 81330021400 in words is "eighty-one billion, three hundred thirty million, twenty-one thousand, four hundred".