81402040 has 32 divisors (see below), whose sum is σ = 184194000. Its totient is φ = 32376064.

The previous prime is 81402031. The next prime is 81402067. The reversal of 81402040 is 4020418.

It is a junction number, because it is equal to n+sod(n) for n = 81401999 and 81402017.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1476 + ... + 12844.

Almost surely, 2^81402040 is an apocalyptic number.

It is an amenable number.

81402040 is an abundant number, since it is smaller than the sum of its proper divisors (102791960).

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

81402040 is a wasteful number, since it uses less digits than its factorization.

81402040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11559 (or 11555 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 81402040 is about 9022.3079087338. The cubic root of 81402040 is about 433.3895443189.

Adding to 81402040 its reverse (4020418), we get a palindrome (85422458).

The spelling of 81402040 in words is "eighty-one million, four hundred two thousand, forty".