81211356 has 24 divisors (see below), whose sum is σ = 210548240. Its totient is φ = 27070416.

The previous prime is 81211349. The next prime is 81211379. The reversal of 81211356 is 65311218.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 375871 + ... + 376086.

Almost surely, 2^81211356 is an apocalyptic number.

It is an amenable number.

81211356 is an abundant number, since it is smaller than the sum of its proper divisors (129336884).

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

81211356 is a wasteful number, since it uses less digits than its factorization.

81211356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751970 (or 751962 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 81211356 is about 9011.7343502791. The cubic root of 81211356 is about 433.0508752294.

The spelling of 81211356 in words is "eighty-one million, two hundred eleven thousand, three hundred fifty-six".