81781106 has 8 divisors (see below), whose sum is σ = 133823664. Its totient is φ = 37173220.

The previous prime is 81781103. The next prime is 81781109. The reversal of 81781106 is 60118718.

It is an interprime number because it is at equal distance from previous prime (81781103) and next prime (81781109).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (81781103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1858640 + ... + 1858683.

It is an arithmetic number, because the mean of its divisors is an integer number (16727958).

Almost surely, 2^81781106 is an apocalyptic number.

81781106 is a deficient number, since it is larger than the sum of its proper divisors (52042558).

81781106 is a wasteful number, since it uses less digits than its factorization.

81781106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3717336.

The product of its (nonzero) digits is 2688, while the sum is 32.

The square root of 81781106 is about 9043.2906621428. The cubic root of 81781106 is about 434.0612264701.

It can be divided in two parts, 81 and 781106, that added together give a palindrome (781187).

The spelling of 81781106 in words is "eighty-one million, seven hundred eighty-one thousand, one hundred six".