81406356 has 12 divisors (see below), whose sum is σ = 189948192. Its totient is φ = 27135448.

The previous prime is 81406343. The next prime is 81406417. The reversal of 81406356 is 65360418.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3391920 + ... + 3391943.

It is an arithmetic number, because the mean of its divisors is an integer number (15829016).

Almost surely, 2^81406356 is an apocalyptic number.

It is an amenable number.

81406356 is an abundant number, since it is smaller than the sum of its proper divisors (108541836).

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

81406356 is a wasteful number, since it uses less digits than its factorization.

81406356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6783870 (or 6783868 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 81406356 is about 9022.5470904839. The cubic root of 81406356 is about 433.3972037347.

The spelling of 81406356 in words is "eighty-one million, four hundred six thousand, three hundred fifty-six".