81401940 has 36 divisors (see below), whose sum is σ = 246919764. Its totient is φ = 21707136.

The previous prime is 81401921. The next prime is 81401953. The reversal of 81401940 is 4910418.

It can be written as a sum of positive squares in 2 ways, for example, as 22695696 + 58706244 = 4764^2 + 7662^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 225937 + ... + 226296.

Almost surely, 2^81401940 is an apocalyptic number.

It is an amenable number.

81401940 is an abundant number, since it is smaller than the sum of its proper divisors (165517824).

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

81401940 is a wasteful number, since it uses less digits than its factorization.

81401940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452248 (or 452243 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 81401940 is about 9022.3023669128. The cubic root of 81401940 is about 433.3893668501.

The spelling of 81401940 in words is "eighty-one million, four hundred one thousand, nine hundred forty".